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?