For some reason, suddenly My Toshiba M30 Laptop started doing funny
things to the display

1. in Windows XP, screen different refresh properly, once i change the
resolution to 640x480 and come back to my previous mode, it is fine
again, but after soemtime it happens again.
2. Screen slowly goes black and comes back again
3. screen doesnt refresh properly, when i scroll the page, we cant see
the contents scrolling, if you switch windows and come back to
previous screen, then we can see the update

I have changed the drivers, though same issue.

When entering into BIOS mode, text on the screen is garbled.

I also, connected external monitor, it displays same faults on
external monitor as well

any idea?