Burnt Smell, Hella Slowdown, what is the source of the problem???

[FairWeatherNerd]

Whats up everyone.
I have a Athlon XP1400 with a Gigabyte Motherboard and no-name 256k of ram running windows xp. Today when I was just watching a movie on it, it shut off. When I went to investigate I immediately noticed the alarming burnt smell seemingly coming from the power supply. The computer booted up again but after a very short period of usage started slowing down SIGNIFICANTLY, it had trouble opening any and all windows and when they were closed they scrolled down the screen like i had a 200 mhz in there or something. Upon further inspection it really did seem to be emanating from the Power Supply however when I replaced it later this evening it worked fine initially but then repeated its earlier slowdown...the computer is unusable in its current state and any suggestions as to the source of the problem would be great.
Thanks alot!

 

[zzzz]

see if the heatsink is making contact and the fan is spinning.
Although the 256K ram might be the culprit too.

 

[Lord Evermore]

If the heatsink wasn't making contact, he wouldn't be able to get on the net to talk about it.

I'm not sure that overheating of an Athlon (from a dead fan) would result in a slowdown of the system -- it would just crash. P4's do slow down when they get too hot, but Athlons don't have that capability; you might get an alarm from the motherboard if the BIOS has that capability, but otherwise you just get errors and crashes.

Still a good idea to verify that all the fans are turning and not full of dust (video card, CPU, case, not PSU since you swapped it). You've checked that it's actually still running at the proper speed? Checked the temperature after it's started slowing down?

The only thing I can think of is the PSU was damaged or defective, and it's damaged the motherboard in some way. I can't imagine what could cause just a reduction of performance, though. Do you have one or two memory modules? Is all the memory detected?