Strange, i'm using Windows 7 Pro 64bits and it runs really fine at my computer. Does the game run, without the restoration mod? Did u also run the config from the launcher to set up your resolution etc? Turn on the force software sound aswell. I had problems with it i believe on my old PC 4 years ago, untill i turned that option on.
While i dont have to use this, but make a new shortcut to the kotor2.exe file and turn on compatible mode on to Windows XP Sp2.
Hope anything of this helps.