Reseating the video card will sometimes fix this, cards have a tendency to creep up in there slots and video cards when undoing systems and setting them backup tend to get the most handling elevating the problem.
So
1)unplug pc
2) set up on a nice work surface preferrably static free,(or on a towel on living room table)
3) open up the case
4) even the static charge of your body with the pc by touching the pc's metal frame.
5) loosen/remove the screw locking the video card down
6) remove card from slot and push card back into slot. Be careful but firm in the pressure you apply, the card should seat itself back in with little to no edges of copper/gold showing at the bottom and the flange needing the screw to hold it down should be fairly flat in the back.
7) put the screw back in and tighten down to lock card in.
8) close case back up
9) set pc back up and reattach all cords and try again.
If this doesn't fix, go into safe mode and reload the video drivers.
If that doesn't fix it then yeah I'ld start considering a new video card. You then need to know if you would use a pci or agp card. You can ask again if you need more input there.
Good Luck!
