Windows protection error

I recently built two machines for a client. They use the same components witht he exception that one has and ATI All-In-Wonder video card and a the other has a Trident Blade. The machine with the Trident 8meg periodically throws a Windows Protection Error at startup. It may require a couple of reboots to come up and works fine from there on. The only other variable is a parallel ZIP drive and a HP Laserjet 5 printer are attached to the Trident carded machine. I have updated all drivers forthe motherboard, video, and sound. I exchanged the video card and the DVD was changed to a Pioneer from an AOPEN. Still happens. Anyone hve any ideas?

DPC