First have you tried? Log in to Search the Forum for help! Learn more about using FreeStyler at the FreeStyler WIKI HERE
Learn more about DMX in General at The DMX Wiki HERE
if all else fails and you need a fixture consider the fixture building service HERE
sounds like its very highly something to do with your Drivers for the dongle, make sure your windows update hasn't downloaded and installed any automatically and make sure you have the latest and correct drivers from your manufacturers website!