Laptop questions? Ask a laptop technician for answers ASAP!
Hi, I'm Mr.med. Welcome to JustAnswer. I'm reviewing your question now, and will post back with your reply ASAP.
I'm sorry about the issue, When did this start and What is the model and brand of your computer please?
This is a hardware issue, The cause is your video cable from your pc to the monitor. Either one of the ends of the cable is loose and needs to be replaced/repaired.
Let me know if you need further assistance
Do you still need help please?