It's also possible that your clutch has failed, which would prevent your transmission from transferring motive force to the wheels.
Will it roll at all if you put it into neutral and try pushing it? If it will not roll at all, then the problem likely has something to do with the brakes. If it will roll, then it's more likely that the problem could have to do with your clutch.
For additional assistance, please find an AskPatty Certified Repair Shop at http://www.askpatty.com/search/?type=all&m=30&q=&keyword= and they can help you diagnose and repair the problem.