You said that you put the card in yourself.....has it done this stretchy thing since it's been installed or has it just started? Is the video set to agp or auto in the BIOS? You may want to check this.
Ok, this is awkward, but....do you have a different monitor you could use? I'm not just throwing out guesses here, or grasping for ideas, but I'd like to rule out the monitor going bad too. I talked to some one today who said they had the same problem, and it was his monitor.
Your refresh rate is ok set at 60hz. Make sure that you're resolution isn't set to high (max res for that card is 2048x1536@60Hz). 1024x768@60hz is good.
In the meanwhile, we're going to try to rule out the grapics card and any/all video issues. Go ahead and update your drivers to the graphics card. Be sure to uninstall them before you install your old ones. When you uninstall your old drivers, it'll ask you to restart the computer. Say no and choose shut down instead. Since you've installed the card before, and are comfortable with the tower and what's inside, go ahead and pull the card out and reseat the card. Also, we're going to install directX 9.0c. You can get it from windows HERE
If this is something that's just started, but you've had the card in for a while and it was fine before, and none of this will fix it, then I'd feel safe saying that it's either the monitor or the card that's gone bad. If it was your power supply, then I should think it would just quit altogether, not just die a little bit.
The first thing I'd do is to try to change out the monitor. If that doesn't work, I'd try to swap out the graphics card. If neither worked, I'd pull my hair out and scream "colorful sentance enhancers"
. Kidding. If that doesn't work, then I'd double check the settings in the BIOS, then as a last resort, I'd try to swap out the power supply.....or this might be the perfect time to build your new machine
Hope this helps! Please let me know how you make out with all these suggestions. If you have any questions, please let me know!