then everything went checkered blue all over the screen, and froze... So i shut the computer off by holding the power button, cause i couldnt Ctrl Alt Delt it, everything was frozen.
now every time i turn it back on, on the startup (those black screens with all the white writing on it) shows up in that blue checker again... there's just scattered blue all over the screen...
Then i get onto my desktop... and everything is huge... The taskbar is three times bigger than it was before... These letters im typing now are enourmous... even the cursor is big.
And when i try to start my cod4 game, i get this error:

can anyone tell me how i can get out of this... or how i can play cod4 again?!?!