my sisters got a 3 year old computer and she recently complained that it sounds like a race car when she watched videos. i have repeatedly told her to bring her computer home so i can put a new fan in for her but she has not listened. one week ago she told me "the noise stopped, hurray!" i figure the fan gave up on her completely. now she complains that her computer is drastically slower. im wondering if it is possible that some of the memory registers or transistors in either her cpu or grafix card blew out because of overheating. can this happen without rendering the computer completely unusable? can overheating cause temporary or perminent slowing in another way?

It indeed can. It's like trying to work in the desert heat. You'd be a lot slower than if you were in a nice air conditioned room.

is it perminant? or will it speed up again when i put a new fan in?

As long as no components have "burnt out" (ie. malfunction beyond repair) the system will be fine once its cooled down. However it is worth noting that the slowdown could be related to other reasons, such as the operating system and its running software. A good vacuum of any dust build up inside can go a long way, too.

When most modern processors start to get hot and overheat, they will lower their clock speed to produce less heat and help the processor from getting too hot. Its highly possible that the "racecar" sound she was hearing was the CPU cooling fan burning out, possibly from age or too much dust built up. Then when the noise stopped, the fan stopped spinning, and thus stopped cooling the processor as well causing it to overheat and slow down.

As long as you can get in there and remove the dust, replace the heatsink fan, and probably add another case fan it will be alright. Just tell her not to run any major CPU heavy programs until then.

what if its the case fan? is there anything bad about not having a working case fan? can the memory registers wear out and still allow the computer to operate?

I have no idea what a memory register is...

Beware of the POWER SUPPLY unit fan, though. Mine gave up on me one day and the cpu was fried.

I have never heard of a memory register wearing out... computer parts theese days are built so that when they get too hot, they reduce the voltage/electricity flowing through them, and reduce speed to prevent damage.

i guess im kind of worrying about my computer now, wondering weather or not formatting fixes everything. it seems slower that it was years ago, but it could be just me.

If you havnt reformatted in a few years, a fresh install of windows could help speed up windows.

quote chopficaro

i guess im kind of worrying about my computer now, wondering weather or not formatting fixes everything. it seems slower that it was years ago, but it could be just me.

really? wow. I've had my laptop since christmas, and it's been kinda warm alot, since I'm on it 24/7. my dad yells at me to vent it, (btw it's a vaio) but I can't find any vents!! i found one on the side, but that's it.
anyway, it get pretty warm, but is as fast as it was the day i got it...oh well.

Being 20 degrees Celsius or 60 degrees Celsius will not change performance.

But, once it hits a certain temperature, it will throttle itself down and that will affect performance. But it's hard to say what the problem is, here. If the CPU fan died, I'm sure it's having to throttle down.

quote Iceguy2003

Being 20 degrees Celsius or 60 degrees Celsius will not change performance.

It is true. But, sure, take the heatsink off and it will be hitting high enough temperatures to start throttling.