have problm in display of computer

If you have a CRT monitor, this often indicates that the monitor itself is on the way out and needs replacing. If you have an LCD or TFT monitor (flat-screen), then it could due to bad connections or dry joints in the monitor itself, in the cables connecting the monitor to the PC or (less likely) a problem with the video drivers. Am I right in thinking that you have a laptop (and a rather old one)? The most likely reason is either wear in the ribbon cable that connects the monitor to the motherboard or a 'dry' joint somewhere. Unfortunately, this needs professional attention and is NOT an easy fault to trace, so it can be expensive, though the cable itself may still be available and not too expensive. It is nearly always the time and labour costs involved which account for most of the price! Take your machine to a reputable dealer and ask for a quotation. Then you will be able to decide whether it is worth your while having the machine repaired or whether the money is better spent on a new machine.