Mbox driver reinstall-reinstall-reinstall

Hi I've been doing this for over 8 years so I'm used to it but does anyone have any suggestions. As long as I leave my Windows 7 Pro 64bit Pc turned on there is never an issue but when ever I need to turn it off, when I turn it back on it does recognize my Mbox 2 Pro and it will have sound if I play a wave file or Media Player etc. But when I bring up a Pro Tools session there is no sound until I close Pro Tools and reinstall the Driver for the Mbox 2 Pro and do a restart then re-open the Pro Tools session and the sound is back. So it is only in Pro Tools after restarting my Pc from a shutdown that I have no sound and need to do a Driver reinstall. Again, as long as I leave my Pc on there is never an issue. I used to think it was the onboard Firewire port on my old Asus P5K Deluxe board but two days ago I got a new Asus Sabertooth Z97 MB and new Processor etc. and hooked up a SIIG Firewire PCIe NN-E20012-S2 with the TI chip and I still have the same odd problem. Why the need for a driver reinstall only after a PC total shutdown? It is not a problem with just a sleep or an actual restart only a complete shutdown.

J.