Hello everyone Trying to fix my brothers old computer that was a custom build and has a microstar-6540 ver.2 S478 motherboard socket. I did a little research, I guess I can take a P4 processor with a 800mhz max speed. I guess I can choose from Celeron/northwood or prescott? Well, I want to choose the right processor for the computer, it's all it needs. Plus I think i need a new fan. But if it's a fan i can take out of one of my random, some older, PCs, then I'll just switch a fan out from another one. But if the processor needs a specific fan to run right and not over heat, i'd like to know. Apparently the case it's in seems to gather alot of heat inside of it for some reason. A friend of my brothers tried to fix and opened up the computer and basically ripped the processor out of the socket and pretty much damaged the pins on the original processor it had in it. unfotunately i'm not aware of what specific processor it was. The sockets still look alright so i guess I'll be ok. Anywho, you're advice please!! Thanks people! Chris