BSOD after changing CPU weird?

[denis280]

HI! guy's just change cpu from athlon iix2 250 to phenom iix2 555. first the pc would boot.power back windows load.and then bsod.restart. everithing look's fine.but 3 min.bsod.so far i moved the heatsink for the thermal paste to sit properly maybe.and now it going wel so far.20 min. what i want to be sure is i should have to format.

asus m4a77d (bios 2201)
8 gb kingston ddr2 800
wd 500gb hhd
psu master cooler 500watt
g-force 9500 gt
windows vista ultimate 64-bit

 

[denis280]

OK Guy's. Works fine now.