If I reboot it's just
:O
It's just what? HIMURRROOOOO
lol But yeah, if its a onboard sound? then try uninstalling then reinstalling the drivers. If its connected through the PCI, Uninstall the Drivers, check the PCI slot make sure the Slot is clean (free of dust) then reconnect it.
I had this problem with my Turtle Beach Montego DDL, I just checked if it was firmly pushed into the slot, reinstalled the drivers and hasn't happened again since.