Been having problems playing movies on DVDs since buying new desktop computer (Vista OS) a while back.

Seems to apply mostly to DVDs I burned myself. When inserting DVD it takes ages for the files to appear, you can hear the noise as the DVD is being read and the progress bar slowly advancing in Explorer.
Then I can finally start playing files when the files appear after about a minute of waiting. Then when I do play back quite often, like every few minutes, movie gets pixelated or freezes.

Extremely irritating!

Don't know what is causing this, maybe it's the blank DVDs I am using (DVD+ ,speed x16), or maybe it's just a crap DVD burner/player? Don't think its the computer itself, it's fast enough it's got a quad processor. Unless Vista is the problem since it did have a dubious reputation at times?

Tried playing back the same discs on XP laptop with dual processor and Sony PlayStation 3 and don't get that problem on those devices, just happens on the desktop computer