Hi winning2013
"i am having the same issue on 2 computers. if i slow down the clip, 2 things happen, sound gets garbled and video turns black. XP and win7. where is the fix?"
If you slow down a clip (i.e. stretch out its playing time) then VP will also stretch out the soundtrack to match making it run slower and therefore play at lower pitch.
You can, however get around this if you create a separate sound file and then use one of the sound manipulation programs that are availbale that will extend a soundtrack without changing the pitch. It generally does this by inserting tiny gaps into the soundtrack that are barely noticeable. The soundtrack is lengthened as a consequence but the pitch is not changed. If carried to extreme however the sound will develop an audible stacatto effect as the gaps become more evident.
No idea why the video disappears though.
Nat