Display changes

Something weird happens now and then with the display on my HP Windows XP laptop. Sometimes the display changes and looks weird, maybe something like interference (RF) getting in somehow. The only way that I have found to fix the problem when it happens is to restore the system to an earlier date. Then maybe a couple of months, sometimes earlier, the same problem will come back. This started a couple of years ago and at that time the laptop was about a year old. Can anyone tell me what is happening? The display has light diagonal lines floating across the screen and text is distorted, I guess caused by the lines that float across the screen. Thanks for any help. Chuck J.