You might try check disk.
Click Start, click run, type 'cmd' without quotes, click OK

You now have a black DOS type window. type chkdsk /f and hit Enter. There should be a notice that it will run check disk on the next start up and fix any issues. NOTE the space before the / but nowhere else.

When was the last time you were inside the case looking for dust bunnies? This might well be a simple heat issue. Let us know what happens in either case listed above.

Thank you for the reply. I unplugged the computer the other day, removed the printer etc. left it overnight, cleaned out the case before getting it into safe mode. Right now I'm trying to get my pictures onto a memory stick - just in case.
I'm afraid if I shut it down, it may not power on again.

When you "cleaned out the case" did you actually use a pure bristle brush or compressed air to remove the build up of dust and dirt under the fan on the processor? This is the fan facing you as you look into the case and is attached to the motherboard. This is the most critical part of the computer and modern computers are designed to shut down if they overheat to protect the processor. NOTE, always remove the power cord when going inside the computer and rest you hand or bare arm on the metal frame of the computer case to dissipate any static electricity.

How did the check disk go? Any useful info or was it good?

Take a look at your 'Event viewer' to see if there are errors reported. You are looking for red error flags.
Click start
click Control panel
click Administrative tools
click Event viewer and a new window appears.
click System on the left side and data appears on the right side

Look down this list for the red error marks and double click on any you find and another window appears. There may be some comments and a clickable link if the comments make no sense to you. Use the link and see what MS has to say about a fix for the issue in question. Repeat as needed for any other error marks.

How much memory is in the computer? Click Start, click Control panel, click System and it should show near the bottom of the new window.

I used a camel hair brush. I'm into event viewer now, and found 4 red X errors in Application, & about 30 in System. I'm going to click them now. System properties General - 1.20 GHz,248MB of RAM.
Thanks for your help.

You are running with barely enough RAM to operate the system. Once you get the problems you find in Event Viewer solved, I would definitely recommend you upgrade the mount of RAM you have. But first things first, find out about the errors, and then come back for more advice re the RAM.

Correction that should be Memory 256MB - Local Disk Total Capacity 74.52GB - Sum of Hard Disks(C) > Used 19.02GB, Free 55.50GB.
One error is: a socket operation was attempted to an unreachable host. Thanks again, I am lost.

Try a system restore from safe mode here is how,

# Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. System Restore starts.
# On the Welcome to System Restore page, click Restore my computer to an earlier time (if it is not already selected), and then click Next.
# On the Select a Restore Point page, click the most recent system restore point in the On this list, click a restore point list, and then click Next.

Note A System Restore message may appear that lists configuration changes that System Restore will make. Click OK.
# On the Confirm Restore Point Selection page, click Next. System Restore restores the previous Windows XP configuration, and then restarts the computer.
# Log on to the computer as Administrator. The System Restore Restoration Complete page is displayed.
# Click OK.

Thanks for the detailed instructions. I have to go out, but will report the results after I give that a try.

Well,I followed the advice from the knowledgeable people here & the computer seems to be okay now. I couldn't have done it without you. Thank you, thank you, thank you for taking the time to help me. I'm doing the happy dance!

Since you have such a small amount of ram I am curious about the Anti Virus program your using. Can you tell me the name of it?

I use Avg & Malawarebytes. How much memory should I have? I'm back to my original problem - the computer works fine for a while & shuts down & restarts randomly. Would doing a restore to an earlier date be an option? Thanks for hanging in there. It can't be easy to assist someone like me lacking in computer skills, & the ability to describe problems properly. I'm not ready to give up.

Sounds like an overheating problem from a fan not working or dust.

I might leave side of the tower case off and aim a small table or big box fan into it for some added cooling. That will give me a chance to observe if fans in it are actually fanning ... & if the restarts instantly go away I'd have a good idea it is a heat related issue.

Sometimes a application can add some heat might look in task manager for something consuming lots of CPU percentage and while there see the percentage of physical memory in use .. maybe its running out & hard drive is running swap so much thats adds a little heat too.

Summer it is not so much about how much memory but more about having enough to work efficiently. 256 megs is bare minimum, 512 is much better and one gigabyte is great as long as the motherboard can handle that amount. Tell us the make and model of your computer please.

I personally would not restore untill you have determined if this is a simple heat issue as Mickie suggests. It may be too much dust and crud inside your tower or a defective fan. You can buy a can of compressed air from Canadian Tire or any computer store. If you do this take the tower outside but allow the computer to come back to room temp before starting if it is a colder day. Also hold you finger on any fan so it does not spin wildly out of control. The most important spot is heat sink underneath that fan facing you on the motherboard as it cools the processor. If you go inside the tower please remove the power cable and rest a hand or bare arm on the metal frame to dissipate static electric.

Cleaning the computer and its components

clean it well, I use an antistatic wrist strap when I go in the case, you can get one at any electronics store for a buck or two. It could be your power supply fan or the power supply going bad. Definitely sounds like a heat issue.
I would sure put a fan blowing on it to help circulate some air.

Also, when the computer shuts down / Restarts do you by see any indication of a Blue Screen it would appear very briefly.

This morning starting up it kept shutting down & making an awful moaning sound. Once started, it heated up on top very quickly.
With the side off, the facing fan is spinning, but the fan inside the box is not.
Owbist I did a restore as per Zeps' instructions on Friday. The computer was used when I got it. Best I can tell it is a Cicero Intel inside Celeron designed for Windows XP. The person I bought it from, upgraded to one for games. I don't do games. I use it for research, email, Microsoft Office, & Pictures & reading computer help, of course.
I've shut it down again & will get an antistatic wrist strap & canned air once the stores open at noon.
I don't think there is a blue screen, unless it is so brief, I miss it.
I've read everything posted here & googled terms I don't understand such as heat sink. I am keeping my fingers crossed that with your help I can resolve the problem.

You will need to replace that fan, if cleaning does not resolve it. In addition put thermo paste on the processor too. See if I can find a set of instructions for you to follow in order to do this. That is if your comfortable doing it.

Here is a video that shows you how to do it See link. You may consider having it done by someone with experience.

Here is a link that might be useful: Replace processor fan.

SUMMER DO NOT ATTEMPT TO REPLACE THAT FAN!

That fan is in the power supply and those things are like a television and hold their charge even after being unplugged. Please do not try to open that box.

If you care to bring your tower to me I will help you with it. I am in Grimsby and from a thread you started long ago in the Canadian Garden forum here at Gardenweb you are also on the peninsula somewhere. My wife and I are here most of the time as we are retired. I do not charge for my services either. Your choice entirely, feel free to email me if you wish by clicking on my handle. With a computer that old you would not want to be putting too much money into repairs and upgrades

oops i thought she meant the mother board fan.

I thought so too at first Zep. At least Summerday seems to have pinpointed the issue with the computer.

I did a little searching and found a thread at Majorgeeks which suggests a capacitor has perhaps gone in Summerday's power supply. Hopefully her noises today have not fried her motherboard as suggested by "Compuable" in the second reply to the thread.

Found these specs in a Craigslist ad in Toronto in October for $100
- Intel Pentium III 1 Ghz processor
- 256 RAM
- 70 GB total storage (40GB main drive, 30GB auxiliary drive)
- Windows XP Home Edition 2002
- LG 8x CD-DVD Burner
- Cicero User Manual (saved as PDF on desktop)
- floppy disc drive in front
- 2 USB ports in rear

Seems a bit expensive for a PIII

Here is a link that might be useful: Cicero computer thread

OMG! I bought a new fan. Fellow told me it was easy to replace. The old fan isn't spinning, but my head is. I won't open up that box. Thanks for the warning.
There is no "obvious" damage to the motherboard; I hope that is a good sign. The moaning sound did stop once the computer started up & it was working nicely, except for being hot.
I'm more determined than ever to see this through.
Owbist, I am in beautiful Niagara & your generous offer is very tempting. You may hear from me.

what fan is it? if you bought a fan then it is not likely that it is the fan in the power supply. How did you determine what fan to buy? Have you tried just taking the side panel off the pc leaving it off and setting a small desk fan blowing on the insides of the pc to see if that helps at all so you know it is heat related. some fans inside the pc do not run constantly some come on and off as the load increases.

The person at the store assured me that was a power supply fan. I'm not sure, so I haven't opened the package. I had intended to see if it matched, once I got into the box. I haven't had the computer on since yesterday.

I'd take owbist up on his kind offer! May you both can sort it out.

zep

this is a suggestion, maybe you can take the side off the tower and take some pictures of the inside especially the fan you suspect to be the culprit and someone here can then have a better idea what exactly it is you are dealing with and you can take a picture of the one your bought or the package.
There are very good picture tutorials online on how to replace fans but as stated working with power supplies can be very dangerous. The other fans are not that difficult to replace. Personally I would consider replacing the entire power supply on a pc that old since it will likely go bad soon anyway and is probably much less powerful than the ones used today so you could upgrade to a much better power supply and that task is easier to take on.

here is a step by step with pics for replacing a power supply fan.
Computer Power Supply Fan Replacement
Here is a nice one with pics for how to replace the entire power supply
How To Replace Your Power Supply

Keep in mind that pc is quite old and out dated so decide just how much you are willing to put into it.
I definitely would take up Owbist on his offer!

Thanks for the links, Ravencajun. My tower gets hot in the power supply area.
Hopefully I'll get those pictures posted tomorrow.