So i got my gaming Pc about 4 months ago, everythng ran great, i suddenly got a black screen, i reinstalled windows 7, and all of its drivers for the graphics card and motherboard, But i now get a warning everytime i start up my pc about a CPU fan Error!, i have intel i5 2500K, with a Hyper Evo 212 gaming fan, it is going down to about 500RPM, then rises a little bit. Is this unsafe?, should i buy a new fan?
Fan will only spin at the speed the bios says is ok for the thermal reading from the chip. If you haven't O/C'd then temps may be ok to run at lowest speed. If you want to play safe, look in the bios for the section that controls fans speeds and change the speed profile.
open the case and check that there no wire in the cpu fan or a clump of dust. most time is a bad cpu fan it not going to hurt the system right now as long as it still working. I would contact the vendor for a new fan (should be free if it under warranty). if you dont want to wait just replace it with a good fan from your local computer store. then put the replacment fan you get under warranty in your spare pile box.