Any idea what could be wrong?

When I watch a .VOB file thru WINDVD4 that I ripped from either SmartRipper or DVD Decrypter 2.4, my screen goes BLACK right around the 4 minute point. The sound continues on, its just the video that quits playing.

It doesn't matter what .vob file I watch, they all do this...

If I fast forward I can see the entire .vob file, but when I start it from
the beginning and watch it untouched, at around 4min bye-bye video.

The only other querky thing going on is that when WINDVD4 opens, a pop-up box keeps coming up asking me to confirm/change my Region Code. Its listed as "Region 1" (which is correct) but it won't allow me to confirm or change it. The only option is to close/cancel the pop-up.

I checked under Device Mgr > then my DVD-ROM Drive > then Advanced Settings and confirmed that "Region 1" is selected.

I need help resolving this...

Things that I've checked:
> Screensaver is off, energystar stuff is off
> I've uninstalled and reinstalled WINDVD4 a few times
> I've checked all my hardware drivers and everything listed as "working properly"

My system (I know is a little old but what the heck):
> Windows 2000 Pro O/S
> HP Vectra PII 450MHz
> 393mb sys ram
> ATI Radeon 7500 video card
> Creative Labs Encore 6x DVD-ROM with DXR3 card
> 30GB Matrox 7200rpm IDE Hard Drive