My son had a hard time playing too. He is very social and seemed to want someone to interact with him all the time. He had a great deal of difficulty doing anything independently. By the time he was 6, I was fed up and decided I needed to do something different. When I looked at our patterns, here is at I saw. I had "limited" TV to 30 minutes a day, but I wasn't consistent with that. It wasn't the same 39 minutes, and if I were in the middle of something when his show ended, 30 minutes turned into 60. When his dad was in charge, TV time could stretch into 2 hours. When he wasn't watching TV, he was pretty much hanging around telling me he was bored and asking me if he could watch TV. Of course, often the answer was no, but sometimes it was yes. Since intermittent reinforcement is the most effective way to reinforce a behavior, I was essentially teaching him to beg for TV.
When I realized this, I decided I needed to set a firm limit. I locked the TV off, and explained that it didn't work any more. Within days, he began to play by himself. Nowadays, TV is a small part of our lives in a flexible, reasonable kind of way, so we were able to reintroduce it!
I also want to second the suggestion to get outside (though it is beastly cold here now!). Nature stimulates imagination and encourages creativity and free play.
