I was going to PhotoShop a Windows 7 options screen with a "Randomly Cause USB Ports To Fail" line checked, but I couldn't be arsed to do it this time...

I'm having the same problem with windows 7. I have disabled all the power saving, run memtest and other tests. My freezes were/are  occuring once a day, or maybe twice a week. I switched the keyboard and mouse to different ports and it's helped a little. This machine is not my DAW but just an off the shelf Dell from Best Buy.

Steve I don't know everything you've tried but I found this too.
Did you run ckdisk yet?
And sorry if this is just added aggravation.

With a new device driver installed, the majority of problems should be resolved. If not, however, you can reinstall the USB controllers, via Start > right-click Computer > Properties > Device Manager > Universal Serial Bus Controllers. Start with the USB Root Hub devices and reinstall the drivers by right-clicking and selecting Uninstall; once this is done, go to Action > Scan for hardware changes… to begin reinstallation.
One last thought – if new drivers don’t resolve the problems you’re facing, try the same device on a different computer; the problem might relate not to the hardware but to your USB cable. If you suspect this, find a good quality replacement cable.

SteveStrummerUK


 
Hang about....
 
 
Would this be it Mark, I've gone direct to the Power Management settings and the USB Selective Suspend setting was Enabled.
 
I've just changed it to Disabled:
 

Was gonna say ... if that does not work, it would be time for another motherboard.
 
And yeah ... takes a while to get past all those small settings in Windows ... now I have to recheck mine on that, although mine likes to go to sleep after 20 minutes even though all the power settings are turned off!