As CRV said try uninstall the offending prog.
It sound like your vid prog is trying to run in Real Mode, but the VxD & DLL is not compatible. Sometime a prog demand Real Mode that run in the Conventional Memory Block where it uses the same memory block as Windows and cause a General Protection Error.
...Sometime uninstall the prog is not enough to cure the problem. If the uninstall don't do it, then you have to restore the Registry by running SCANREG/RESTORE at dos promt, and WSCANREG/RESTORE in Windows.