computer needs to restart?

Hi, I have an ibook G3 (late 2001) I recently added 512MB ram for a total of 576MB. My computer was definitely running a lot better, but something odd has started happening, when the computer has been running for about 30-40 mminutes, a black box appears in the center of the screen saying that the computer needs to be restarted and that I should hold down the power button. This is crippling! Any ideas on what is going on?

Have you tried cleaning out your temp files? I was getting that error on my machine for a bit... I cleaned out all of my temps and the issue was resolved. Turns out that OS X is built of Unix, and Unix cleans its own temps out between the hours of 3am-5am. However, most of us don't leave our computers on at night and this clean up process does not get done. You can invoke it manually by going to the following link:

http://www.macattorney.com/ts.html

The other links are very helpful too. Good luck and let me know how you make out.

Also it may be that your machine is getting to hot...do you have a lappy or desktop?

Hi, thanks for your advice. I went to macattorny.com and followed some of their advice. Specifically, I did a safe boot, and I repaired disk permission and since then I haven't had any problems, thanks again!

your problem is a kernel panic caused by bad ram, take the ram out and send it back, get it replaced with a different chip.

Yeah, I've seen that kernel panic message before. For some reason though, the "needs to restart" message has stopped appearing. Is it possible for the problem to disappear or is it a ticking time-bomb?