That was me a few years ago. Best thing to do is just force yourself not to. Sit outside, ask a friend to come round, do some school/college work. Distract yourself. There's never much to do at home so I too spend most of my time in front of the computer but at the end of the day, productivity is possible while doing this.
I realise this thread isn't entirely serious but it does happen to people. It's just an addiction, one that can be easily broken.