liveitup, FYI - I've upgraded both my PC's running MC12 (one is a dedicated HTPC, the other the Main Family PC) to Vista after alot of testing. I found there are issues with both Vista and XP but on balance I have found that for me Vista is a better platform for MC12 than XP.
The Vista/MC12 issues I see are:
1) In T'View you sometime see the Vista Desktop: Sometimes when playing Videos, T'View will disapear for a few seconds before the video starts letting you see the Vista Desktop
2) T'View loss of focus / not in front: I've not had this for a while but sometime (not sure how) MC would lose focus so RC commands will not work till I "Alt-Tab" back to MC12. Even odder is when MC12 appears to be on the top, and does have focus yet the bottom windows menu bar is visible - again "Alt-Tab" will fix but not ideal as this needs the K'Board to come out...
3) MC12 Hanging / Non-Responsive: If I'm playing with filter selections I can get MC12 to Hang / become Non-Responsive easily. Vista then pops up the "Do you want to close the non-responsive app" Diag Box, I close MC12, Start it again, change my poor filter selection!
So my guess is it is a bad filter combo that your suffering - the great thing is the MC12 lets you pick and choose these - no other app lets you work around these problems!
Thanks
Nathan