Windows 7: VOB's won't play in Media Center, but will in VLC. Ideas?

Hello, I'm new around here. I'm using Windows 7 media center. I have a fair number of my DVDs backed up to VOB files (VIDEO_TS and AUDIO_TS folders) using DVDFab (full backup, probably with the option to remove 'annoying PSGs')

The problem I'm having is that in Media Center, some of them just won't play. The screen turns black and nothing happens. Right before it turns black, Media Center dings twice (but I don't see any error).

The ones that don't play in media center DO play in VLC. I've heard that VLC uses it's own decoder or something, which might explain that.

Anyway, I've tried several codec packs (k-lite, shark007, etc.) in both 32-bit and 64-bit versions, to no avail.

After weeks of playing with it, I almost have my media center set up perfectly except for this rather annoying problem. Any ideas?

Thanks,
Chris