This is a concern for many, many parents these days. Of course you should do all you can to engage him in other activities. But I don’t think just removing the computer is going to do much good. Most kids will have a major tantrum if you separate them from the gaming and “friends” they have online. Weaning away by setting some limits is more likely to be successful.
Before you try to enforce some new rules for computer use, do think about why your son is spending so much time in a virtual reality. Does he have friends to hang out with? Is he having difficulties in school? Is he withdrawing from the family and the social world because he is depressed, socially anxious, or avoiding what he sees as social or academic failure? If so, he may need to see a counselor to help him figure out how to manage his problems instead of avoiding them.
On the other hand, you say he has a diagnosis of Aspergers. Often, kids with Aspergers have a very narrow range of interests. What looks like OCD is actually a feature of the autism spectrum. It may be that his “obsession” with the video games is an expression of that rather than a social or psychological problem.
I’m concerned that you and your son aren’t getting enough support to help him through the teen years. Often the special education department in schools provides individual instruction in social skills and time management as well as academics for students on the spectrum. Often, that same department can also provide some guidance for parents. In some cases, there are parent support groups for parents of kids with Aspergers and other differences.
Please seek out whatever help may be available. Then take it from there.
I wish you well.