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?

but the cpu would not have lasted too long if the fan gave up completely as overheting would have ruined it. I'd say the fan might still be working otherwise the PC would hae shut down due to oerheating by now. Have to say if the fan is gone and she is still using the pc then its not too long that the pc will give up as well.