As you have downloaded Malwarebytes you should also grab the latest definitions, the link is below. I think I would install that, update it and run in safe mode with the internet cable removed. While there I might run Avast and/or Superantispyware to be doubly sure I had done my utmost to be clean.

Here is a link that might be useful: Malwarebytes latest definitions

Thanks, owbist. There was no reply when I checked this morning. I did get the latest definitions before running Malwarebytes. I didn't run it in safe mode, however... The log is below:

Malwarebytes' Anti-Malware 1.36
Database version: 1945
Windows 5.1.2600 Service Pack 2

4/25/2009 8:54:38 AM
mbam-log-2009-04-25 (08-54-38).txt

Scan type: Full Scan (C:\:)
Objects scanned: 159911
Time elapsed: 39 minute(s), 31 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 0
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 0

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
(No malicious items detected)

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
(No malicious items detected)

I'll update Avast, go into safe mode, and run another scan.

try going to an online virus scan and running a scan there
FREE Online Virus Scan

I've been running a thorough Avast scan in safe mode for a couple of hours. It's never moved off 0% complete after scanning 98,000 files. I stopped Avast and am going to run raven's online scan.

Hmm, it is entirely possible that your Avast is corrupt. Perhaps either install over itself or remove and install again. Be sure to copy and paste the registration number in to a Notepad file so you can register again.

I was running raven's scan. All was going well-no threats found. When I retuned later, I had a blue screen with this message (the first line had no page above it:)

for any windows updates you might need.

Run the driver verifier against any new (or suspect) drivers. If that doesn't reveal the corrupting driver, try enabling special pool. Both of these features are intended to catch the corruption at an earlier point where the offending driver can be identified.

If you need to use safe mode (explains how to enter...)

If this is the first time you've seen this stop error screen, restart your computer. If this screen appears again, follow these steps:

Check to make sure any new hardware or software is properly installed. If this is a new installation, ask your hardware or software manufacturer for any windows updates you might need.

If problems continue, disable or remove any newly installed hardware or software. Disable BIOS memory options such as caching or shadowing. If you need to use safe mode to remove or disable components, restart your computer, press F8...

Technical Information
***STOP:0X000000C5 (0X00000004, 0X00000002, 0X00000001, 0X8054A1FA)

Beginning dump of physical memory.
Physical memory dump complete.
Contact system administrator or technical support group for further assistance.

END OF MESSAGE

When I restarted the pc, I went into safe mode, shut it down and will wait for an interpretation of the above! :) I have not installed any new hardware or software. Thanks for your help... Much appreciated!

Owbist, I was wondering if Avast should be uninstalled and reinstalled. Thanks.

I think I would uninstall avast you can do that in safe mode if you want then install the latest version of avast, you can download the newest version prior to uninstall of the one you have. It sounds like it could be a corrupt avast file.

another online scan you can try
BitDefender Online Scanner

Several things to report:
When I booted my pc, I received this message...
System has recovered from a serious error.
A log of this error has been created.

Error signature
BCCode:100000c5 BCP1:00000004 BCP2:00000002 BCP3:00000001
BCP4:8054A1FA OSVer:5_1_2600 SP:2_0 Product:768_1

The following shows the files included in this error report:
C:\DOCUME~1\charlene\LOCALS~1\Temp\WERc08b.dir00\Mini042509-01.dmp
C:\DOCUME~1\charlene\LOCALS~1\Temp\WERc08b.dir00\sysdata.xml

At this point I went into safe mode to install Avast (had downloaded latest version to a flash drive). However, I suddenly realized that I forgot to uninstall the possibly corrupted version and canceled the install. My computer immediately froze. I wasn't expecting this to happen in safe mode... I shut down the pc and decided I better go to bed! :)

This morning I went into safe mode, removed the old copy of Avast, restarted the pc, returned to safe mode, and attempted to install Avast. However, I received an installation error which follows:

26.04.2009 06:59:01 general: Started: 26.04.2009, 06:59:01
26.04.2009 06:59:01 system: Operating system: WindowsXP ver 5.1, build 2600, sp 2.0 [Service Pack 2]
26.04.2009 06:59:01 system: Memory: 14% load. Phys:1337544/1570892K free, Page:2154928/2207244K free, Virt:2071324/2097024K free
26.04.2009 06:59:01 system: Computer WinName: CHAR
26.04.2009 06:59:01 system: Windows Net User: CHAR\charlene
26.04.2009 06:59:01 general: Old version: ffffffff (-1)
26.04.2009 06:59:01 system: Using temp: C:\DOCUME~1\charlene\LOCALS~1\Temp\_av_inet.tm~a00896 (52320M free)
26.04.2009 06:59:01 internet: SYNCER: Type: use IE settings
26.04.2009 06:59:01 internet: SYNCER: Auth: another authentication, use WinInet
26.04.2009 06:59:01 general: Install check: Program folder does NOT exist in registry
26.04.2009 06:59:01 general: SGW32P::CheckIfInstalled set m_bAlreadyInstalled to 0
26.04.2009 06:59:04 general: progress thread start
26.04.2009 06:59:05 general: Destination: C:\DOCUME~1\charlene\LOCALS~1\Temp\_av_inet.tm~a00896
26.04.2009 06:59:05 general: Starting download: http://www.avast.com/go.php?verb=get-avast-home&type=cnet&langid=eng
26.04.2009 06:59:05 internet: ERROR:HttpGetWininet, catch returned 0x00002EE7
26.04.2009 06:59:05 general: Download finished from server www.avast.com, result: 0x20000004, server response: 12007
26.04.2009 06:59:05 general: Stats www.avast.com, server response: 536870916
26.04.2009 06:59:05 general: POST result: 0x20000004, server response: 0

Thank you, dear people, for your help! I'll check back later.

Raven, I'm going to try the other online scan. Thanks.

Avast has an uninstaller tool - is that how you uninstalled it ?

You probably should never stop most installs or uninstalls. Hopefully that tool cleans up for you.

Here is a link that might be useful: http://www.avast.com/eng/avast-uninstall-utility.html

Mikie... I used the Add-Remove Programs to uninstall. I downloaded the removal tool and searched for Avast files. There was really nothing on which to use the tool. I deleted the small traces the search found.

I tried once more to install Avast in Safe Mode, and the pc froze again. I decided to do a normal boot and install. When the install began, ZA indicated Avast was trying to connect to the internet. (I had disconnected my DSL.) I reconnected and all went well. After installing the license key, I had Avast do a thorough scan which showed no problems found. I also did the online scan with BitDefender. No problems were found.

Apparently the previous version of Avast became corrupt and needed changed. Could the fact that my internet connection was unplugged cause the install of Avast in safe mode to freeze my computer???

What a relief! :) Thanks, Everyone.

I don't remember needing to install any programs lately in safe mode & I do use avast and uninstalled/reinstlled avast after IE8 fairly recently.

Many things windows will fail install from safe mode.. so unless it tells you to do a safe install...

Some programs when you 'download' to do an offline install actually only give you an installer but not the full install which they do go online and get the proper package for your version of windows. That way they don't need to worry about discovering from what your browser says you have maybe incorrectly or send you a one file fits all version wasting your time downloading lots of things you don't need and their precious connection bytes too.

Thanks for the explanation, Mikie. It makes sense...