I have a verical line on my pc monitor

Cactus Cartoon a single vertical line is most commonly caused by a TAB error. That is where the small ribbon cable that enters the actual LCD panel has come loose. You can check that by putting some pressure on the LCD panel where the line appears. If that changes it you know it is a TAB error. Hard to repair for DIY'er. We would need to know what make and model your monitor is and what your screen shows. Post some good images with your question so that we can see what you see. Use this guide for that Adding images to an existing question