IRQL_NOT_LESS_OR_EQUAL HELP!!!!

[YoungRogue]

i have started receiving this message in the form of a blue screen of death, so far only when i have been playing call of duty 4 and it doesnt happen often but its happened about 4 times now in the past month, it just did it again and im getting a bit worried lol any ideas?

 

[YoungRogue]

there must be some reason that is causing it it hasnt always done it tho.

 

[YoungRogue]

my cpu rarely goes above 50 degrees, its an e2160 running at 2797.2mhz
my graphics card is an 8800gs, and i have 2gb of geil platinum stuff altho thats clocked at just over 900mhz, stock is 800mhz. but it has all been running fine for the past 4-5 months or so.. so far it has only done it in call of duty 4, i play command and conquor 3 aswell but when i play cod4 i am on it for a few hours at a time.