Computer freezes, keyboard lights light up

Hi, recently one of my comps been acting weird.
For no apparent reason it freesez, all the lights on keyboard light up (Caps lock, Num lock and Scroll lock) but nothing functions. I tried rebooting it sevarl times without luck, if i leave it off for a while and then turn it back on then it works for short period of time but eventually freesez again with symptomes discribed above.
I changed PSU with a more powerfull one, but it didnt fix the problem. Any ideas?

Comp specs: (if you need any detailed info let me know)
Intel PIII 1ghz
512 mb sdram
64 mb ati tnt videocard
Windows 2000 pro

thanks

wild guess here, is it overheating?

good guess, didnt think of that one
i'll try to get to BIOS and check my hardware monitor and post the temp

k, cause i have heard of comps just freezing and not working at all if the temp gets too high so nothing really bad happens

check the inside of your tower, a lot of people never clean the dust out of their computer (it can be really bad in most cases), that really messes with the cooling.

yea that was gonna be my second suggestion

Even if your tried a new psu, make sure that whatever you use has enough amps. The other possibility is your ram, try switching it around.

Or running Memtest86. I'd go with the overheating issue though, turn off SMART Fan or Cool n' Quiet if it has it, and see if the HSF is clogged up with dust.

howd everything work out?