Sounds like a video issue from what you have said. Does it use onboard video or does it have a stand alone video card? Ready made computer or clone?, a little more info would help. If video issue can be a pretty simple fix.
My PC has a no video input problem. It was working fine in the morning but in the afternoon it didn't boot up properly. It has strange red streaks across my normal bootup screen, some of the words are changed as well. It didn't get to the Windows XP screen and suddenly, the screen went blank and it shows "No Video Input" but my CPU is still on and working.
Later, thinking it was a monitor problem I switched it to another monitor to try. It worked fine. Then I shut it down and boot it up again for another try. Then the strange streaks of colour appear on screen. This time, it shows the Windows XP screen but the colour were wrong. It manages to boot up and I could work properly and the images on screen are correct.
Later on in the day, I switched it back to my old monitor and everything was fine except, it couldn't get pass to the Window XP screen.
Strangly enought when i try my original monitor on another PC, it works fine.
I've tried System Restore even though I have not installed any new programmes. Is this a virus problem? Or is there something wrong with my graphic card or my RAM?
I am running a Intel Duo Core 1.86 Ghz, MSI P965 MOther board, 1GB Ram, Windows XP SP2.
Currently, I am able to go into safe mode, though there are still the strange streaks of color on the screen. And I am doing a virus scan. Will update on the status of the problem. Will appreciate any help or solutions. Thanks!