Could be a problem with the video driver or the hardware (most likely the video card, possibly the monitor).
I'd check device manager to see if there are problems with the driver. And anyway I'd reinstall the driver before running dxdiag (Direct X diagnostics). If that shows errors, I'd redownload the latest Direct X for your OS from download.microsoft.com and install that. If still no luck, I'd buy another videocard.
i have p4 3.00ghz 1128mb ddr1 ram ...nvidia geforce fx 5700le 128mb
when try to start a game (lineage 2,Battlefield 2 ,,and more ,,this games work before 2 days perfectly) show me crazy things and colors at screen