So i just got my 320GB external hard drive in for time machine. I plug it in and it starts to back up but then seems to freeze(its staying at 1.3 GB backed up for several min) so i decide to restart. After restart my volume icon is now blank in the menu bar, if I try to adjust volume the overlay is grayed out and in system preferences it says "No output device found". So its seems OS 10.5 has misplaced my sound card. Any help would be much appreciated, oh and my system is in my sig.