Strange problem with my CPU

i run a q6600 (no OC)
a 8800gt(oc'd lil)
and cooler master 460 watts extreme power plus

recently my computer temps were hiking at around 45c to 50c idling and over 80c at load.
i thot it was problem with the thermal paste and the seating of the heatsink. so i removed and re-applied the paste(the razor thin layer way), and attached my heatsink back(stock heatsink with those clips).

on the process of tightening i think i made a contact the screw driver(flat head) with the motherboard. there are no visible marks on the mother board.

but now i face another problem where my comp is idling at 50c and load 92c """". and very often even at 0 load condition my comp freezes(mainly when i use WMP), strangly i m able to move the mouse pointer, able to play red faction guerrilla etc.... no problems. but the freeze happens only when there is no load(At least as far as what i've seen till now)

could it be the motherboard due to the contact or could it be the temps??
And i m running on windows 7 beta btw.

Check the speed of the processor. And check too if some blade of the fan of the heatsink is broken.