it sounds like something is already using the port. do you have skype or steam or IIS running? if so, kill them and try again. if not, go ahead and reboot and immediately run the app once the PC boots. if that doesn;t do it, you should probably go into msconfig and disable anything that isn't vital(basically, disable almost everything) and then reboot and try again. at that point it should work. then you can go through msconfig re-enabling stuf again until you figure out what was doing it.