I'VE RECENTLY INSTALLED A NEW HDD AFTER FAILURE OF THE ORIGINAL. I'VE NOW GOT IT ALL UP AND RUNNING AND NOW FIND THAT THE DVD DRIVE WILL PLAY A DISK ONCE ONLY I.E. IF AFTER INITIAL SWITCH ON I USE THE DRIVE IT WILL HAPPILY PLAY ANY DISK; HOWEVER WHEN I EJECT AND PUT ANY OR THE SAME DISK BACK IN IT FREEZES UP THE COMPUTER WHICH IN TURN CAN ONLY BE UN-FROZEN BY A POWER DOWN....