Co writes in with a hardware question.
Question:Problem: gray lines appear behind any text, text boxes and pictures, and extend all the way across the screen. Each gray line is almost the height of the text or box or picture. My cp unit is about 6 yrs. Old. I've tried a different monitors and the same thing happens so I know it has nothing to do with the monitor. Thank you for any help you can give me.
Answer: Since you tried the first step which is replacing the monitor the next step is to concentrate on the video card. There are a few things you can try. The first is to update the driver with the latest version. If you don't know what your video card is then you can go to Device Manager to find out and then find driver online.
You can also boot into Safe Mode which will use a generic driver for your video card and see if you get the same results. If so then its not the driver.
If that doesn't work then you can try moving your video card to a different PCI slot if its a PCI video card. If its an AGP card or onboard card then this wont be an option since you only have one AGP slot and cant remove an onboard video card.
Finally you can replace the video card since there is a good chance it is bad. If you have a spare or can borrow one then you can do a test before you buy. Or you can always take the card back if you buy a new one and its not the case.