It is definitely an interrupt problem (and driver, and DMA etc etc).
Now got to the stage of having an up and running system with network card/Firewire card/Turtle sound card/USB printer/USB smart card (camera reader) and USB ZIP250.
Had to sweat blood with each and every one of them woth latest drivers (some dated 13/11/2000!) to get this far.
Just tried to load a USB camera (Chicony VC-350) and that is now locking the system up as well. I suppose I need their latest driver as well!
After that the last thing is the USB scanner (HP scanjet 5300C).
Of interest, the solution to the last set of lock ups was the Doc Solomon (McAfee) Virus scan, I uninstalled it, and I uninstalled the motherboard software RAID from the control panel. Everything then loaded.
The hardware configuration for each new device does take the system 15-20 minutes to sort out and load!