Video Gone Mad

After 8 months of successful XP operation on a Gateway
machine, today I have vertical lines in the display, and
am unable to start the machine normally; currently in safe
mode.

GW tells me the video card a 3Dfx Voodoo AGP is not
compatible with XP, and I need to go back to W98. For 7
months XP and my video card seemed to like one another,
could I have taken in an auto MS update and caused this?
Did, could my video card have failed?

Besides the inability to boot up the machine in anything
other than the safe mode, I have vertical lines. The
lines are typically purple or black, run top to bottom,
straight. The screen is also unreadable when I scroll;
shadows of text on top one another. Not sure what I'm
typing at times.

Any ideas?