try different drivers, I know there are a few out there. I use the ones that come bundled with the Radiator software (I got it here ).
Also, there is a known issue that if you resume from hibernate (standby too???) and then try to use the radio the system will restart. Something to do with Windows XP not refreshing USB drivers on resume or something... no known fix that I know of yet. But the radio still should work off of a fresh boot.