GeForce 7900GS Graphics Streaks During Gaming

I have an original  Nividia GEForce 7900 GS card in my less than one year old XPS/Dimension 400/9150 with a 1680x1050 display DELL LCD 20" Ultrasharp Monitor , and the graphics have started streaking across the screen when playing games.  It seems like it can't resolve point geometry, and a point will extend as a line or shape from the point to the edge of the screen - almost like it is unable to calculate the correct end point.  This was first noticed in Lego Star Wars II (thought it was bugs in the game), but now it is happening during World of Warcraft (not exactly a graphics demanding game) and I'm running 2GB of RAM.  Does this mean my graphics card is going bad?  I've never had a card go bad in any computer before, so I don't know what to expect - but it was fine until about 2 months ago.