i've installed a new box-packed Intel P4 2.66 GHz. on an Intel 915 GAV MBrd. The average processor temperature remains at 55 degree Centigrade! while installing the heatsink-fan assembly, despite a lot of manouvering i was unable to get the fan screws to 'click' into the MBrd as the instruction booklet'd specified - though the fan appears to be firmly in place and does not move...on recent examination it was also observed that the thermal grease layer had somewhat depleted! what's going on? please help.