I've been having problems with my PC making a grinding noise under anything other than very light load (browsing/email) - it's a quite powerful rig 'n all. If I go into the BIOS the noise is horrendous. The CPU temperature is at 60 degrees, but falls rapidly to 40 and the noise stops. If I set the CPU fan to full, the noise and overheating return. I spoke to the guys I bought it from (CyberPower); they asked me to check if the noise stops if I detach the pump from the motherboard - it did. They said the pump was done for and to return it. I also told them that the 'physical' fan that comes with the H55 isn't spinning - like not one tiny jot - nada. This didn't alter their diagnosis. I'm happy to return it, but I just wonder why the fan never spins. Perhaps I'm being really think and stupid, but I wonder if anyone could confirm that the fan not spinning is symptomatic of the pump being broken. What would be 'normal' behaviour for this fan?