Something similar has happened to me during last 6 months... but 10 years - man, you are in your own category. The biggest issue is that after a while you get used to that time wasting, you simply start living like that.

The only thing that I can advise (and that helped me a bit) is to make a change, ANY change. Even picking something addictive like http://na.leagueoflegends.com and playing it helps if you make a __realistic__ goal (I'll get to XX elo) and then follow up to getting to that point. Satisfaction mostly comes from making the goals you set and probably your biggest problem was that you had no motivation even to set the goals (that's why I suggested something addictive in which it'll be easy to get motivation for goal setting).