[Solved] Graphics Card Destroyed?

I'm having a problem which is doubtless related to my new graphics card (a GeForce GTX 260), my power supply, and my own stupidity.

I installed the card and used it for a week with wonderful performance. Recently, however, I have started noticing some slight artifacting and vertical lines after about an hour of use with a graphics heavy game. If I let it sit powered down for a while, it gets better. I did some troubleshooting and discovered that my power supply didn't meet the specifications for the card (when I bought the power supply it was pretty robust, but that was ages ago -- in any case I should have checked before I charged forward with the installation).

Now, I'm assuming that the insufficient amps produced by the power supply is the problem here. My question is this: do you think that buying a new power supply will fix the problem, or has the card been damaged by being used with an underspecced power supply? I just want to know what is most likely before I decide how to proceed with upgrades.

The GPU is unlikely to be damaged by being underpowered unless it has been overheated by the fan not functioning, just get a better PSU.

First, thanks to everyone for your responses.

I decided to try to switch back to my old video card while I waited for a moment to get my new power supply, but the only problem is that the problems are persisting. I still get (after about 30 min or 1 hour) vertical lines forming on the screen and fuzzy patches of discolored pixels here and there. It seems that by stressing the power supply with my new card I've broken some other piece of hardware.

Do you guys have any idea what (ther than a video card) might be causing these problems? Did I somehow fry my motherboard? my RAM? my CPU?

Try a different monitor, it could be the screen at fault you know!