This is a serious problem, glad you recognize that.  Not clear what you have tried on your own.  Do you have a friend you trust who would be able to help out?  Your friend could put a password on your computer startup and then he or she would need to give you access to the computer only when you need it for legitimate communication or work.  Realize this doesn't sound very convenient. The other thing you could do is talk to a mental health professional.  Addictions often develop because of other adjustment issues including relationship problems.  If that's the case, then the other issues need to be addressed before the addiction can be resolved.  See the web site below for other information.

Jeanne H. Brockmyer, Ph. D.
education.com expert clinical psychologist