8800gt is not enuf 2 run crysis.
I use GTX 260 with 4gb ocz reaper ddr3 rAM, amd phenom 550 3.7GhzCPU and i still only get around 40fps.
So with a 8800gts thats 2 much 4 it 2 handle.
best thing 2 do wud b 2 upgrade the graphics card.
Just upgrade your HDD, 20GB is wayyyy to low you know.
But for now just get another comp plug in your HDD and format it and re-install windows.
ORRRR
Just re-install windows (this wipes clean the whole HDD)