I just shared this w the Gecko drive people and they said they had a similar problem a couple of months ago.
I had a G540, Mach, 3 Vista 32 bit, Parallel Card interface.
Every time I turned the G540 on, as soon as the drives powered up, the computer would lock up.
It did it even when Mach was not running...(that took me a while to figure out).
To make a long story short, the problem turned out to me my wireless mouse transmitter.
The wireless mouse transmitter was in the back of the computer next to the parallel port cable.
When I moved the transmitter to the front of the computer, everything worked.
Some key points to the problem...
1. the mouse would stop moving as soon as the G540 was turned on..., the mouse would starting working again as soon as the G540 was turned off...it had nothing to do w Mach.
2. I had a wired USB keyboard, even though it looked like the computer was locked up, I found out that the computer was not locked up, the keyboard still worked.
3. Moving the USB transmitter to the front solved the problem.
Hope this helps someone.
It stumped me for a while.
Love my Gecko G540 and Mach 3.