Hey...I have a ASUS P5N-SLI mobo and everything worked fine and then all of a sudden i turn it off and back on (properly) and it beeps saying the cpu fan is not working...I plugged it in a few different fan locations that were currently working and it still failed to power on even after being turned off and back on....I checked the temperature and the CPU was htting 70 so i turned it off and have left it off as ive seen that temp can be very dangerous...Does anyone have any suggestions for fixing? It is a watercooled fan by coolermaster..I can give more details if needed...Thanks for reading and hopefully someone can help

Should still be under warranty. CPU fans can fail anytime without warning, but most last a remarkably long time.

Second that...

Just RMA the HSF unit, or if that is to much of a bother you can go down to any well equiped computer store and buy a replacment fan of the same specs.

Changing it a snap (usually just 4 screws or 2 brackets) unless it is some kind of funky assembly that you cant take the fan off, then your best bet is to RMA.

I dont think the fan on your unit is anything hight output (high rpm) due to the integrated water cooling on the device so just about any case fan right around 18 cfm should do the job. Just make sure the replacment fan has a 3-pin fan connector not a 4 pin molex.