First, do you have a Realtor? If not, that would be the problem. I see so many people with simply a small yard sign, with faded writing so you can't see the number, in a gated neighborhood. It amazes me that these folks wonder why they get no calls.
If you do have a Realtor marketing your home, it is most likely overpriced. In some areas, even the lowest priced listings are still overpriced. If you're not getting any showings, that is the most likely issue.
I agree with Stephanie that you do want to visit with your agent and review their marketing plan. If it does not include a heavy emphasis on internet advertising, you're missing 90% of the home buyers out there.