are you using it on your lap on a soft surface that could be closing off the vents on the bottom? Laptops will get very over heated if their vents are not fully open and over heating will cause one to shut off to prevent further damages, the noise could be a fan that is going bad. I think I would have it looked at. You can buy air circulating pads to put a laptop on that have little fans in them which help to keep them cool and the air circulating under them. here are a couple of different type examples Cooler Master Notepal X2 Notebook Cooler R9-NBC-4WAK-GP Cooler Master Notepal U2 Notebook Cooler with Two Fans be sure you read the reviews on the laptop coolers because some are not worth the money. Also some use the power of the pc through the usb port and some plug into a power supply, those have much more power and strength to cool with out tasking the laptop usb power supply. When it does this is it running on battery power on plugged in? could make a difference, many will run hot with battery.

Let's see if I can explain in the limited time I have; if I don't finish, I'll come back later or tomorrow. Have hubby's last chemo & radiation today. In my office I have a dual boot Windows machine - running XP (pro I think) and Vista. I also have the Mac. I have not tried to put Windows of any flavor on the Mac; it was on my list of things to do. I was going to buy the program verses what's on the Mac. My pain management Dr did it; he had some issues with drivers. Not sure if he did XP or Vista. The Mac worked fine at 1st. I was able to Network; I was able to access the Windows machine both sides. When on the Windows PC; I was able to access the Mac from both. I'm not sure what changed and when but eventually I wasn't able to access either puter - I made user accounts on Windows (both sides) and now am able to access Windows (both sides) from the Mac. The problem is accessing the Mac from Windows. Granted, it very well may be me; because I haven't been as "heavy" into building & using the computer since we moved. The most I do is work with pictures; for that I use Windows because the Mac photo program confuses me. I like Windows much better all the way around because of ease of use; software works & I can do things without reading a manual. With the Mac, I feel so stupid some days. I haven't installed anything except firefox.. forgot how. lol It's so simple too from what I remember but I have to get the dummy book to do it again. lol One thing that will not work on the Mac is my Microsoft Works. All of my medical databases are made with works. I looked for a Mac plug in (reader) but they don't have one. I also don't want to have to replace my full Office suite.

Wow, gardenspice, I'm sorry to hear of your malfunctions. Since my first Apple computer - a //c that I got in 1984, I've never had a hardware problem. I've had a probably a half a dozen Macs over these last 25 years and never had a hardware problem. It's one of the reasons I've been a loyal Apple Computer customer. And now that they have Apple stores, I can get help with questions or buy new equipment quickly and painlessly. Apple rocks!!

Chispa, I just learned about the swelling and ruining of the Macbook issue, but the good news is that that is apparently a safety feature as the battery failure is contained by the laptop; with the others, they can apparently explode all over a room and set the house afire. I can't be replacing my Macbook at this time, so I really need to get my ancient battery replaced! Tina, from now on, I will always shut down when I'm not home, and will never leave it plugged in overnight or when I'm not home, either! I'm still kinda shocked at how careless I've been and how fortunate that I didn't create a disaster through my ignorance.