As for video stuck on one frame while audio continues playing. Sounds like you are trying to deal with an old avi codec that CS4 doesn’t recognise.
I had this before when someone handed me some footage to edit. They had exported as .avi but from a camera that was an ancient relic !
Turns out I needed the mjpg decompressor. You may need a different one depending on what camera the footage came from. I discovered which one I needed by dropping the problem clip into AE project panel then tried to play it directly in the project panel (don’t play it from a composition as it will play fine in comp windows). When playing in project panel it came up with :
“can’t find vids:mjpg decompressor”
here’s a link to the mjpg decompressor if you need it
https://smart.pannoninteraktiv.hu/video/codec/mcjpg30.zip
after installing (by following readme notes in the zip)close Prem cs4 then reopen the project so it can recognise the missing Codec….Voila ! fixed.
http://WWW.FootageNest.com