Cant change desktop resolution

so im on xp pro sp2 and i cant change my desktop resolution, or i can move the resolution bar but when i apply any resolution screen flickers and ask if i wanna se these new settings (what ever i do resolution wont change. the resolution will be 640 x 480 or so

ive tried everything updated display card driver and monitor drivers reinstalled em many time, flashed bios, nothing.

also when i play a game (games working fine and i can change resolution properly) and return to desktop or boot my computer my resolution will be 640 x 480 or so. windows wont remember resolution/color depth settings somehow???? this is frustrating

Also when i boot my comp again in that same 640 res and unistall display card drivers and boot resolution changes a bit but when i install new display card drivers boom 1920x1200x32bbp nice looking desktop untill i play a game and return to desktop or boot my computer and here we are again 640 x 480 resolution.

Do i have to format c (what a nightmare) or whats going on. is my display card or motherboard broken perhaps?

i have a Benq G2400WD monitor and nvidia geforce 7600gs agp

like i said this problem is killing me please help any clue?

Sorry for my shitty english