This is just a thought...
Is the problem only with this cassette? If so...
Is the country of origin of the video cassette the same as the video recorder you are attempting to play it on?
Check the spine of the cassette for NTSC (USA) @ 60Hz sync. or PAL (UK) 50Hz sync. format. Just sounds similar symptoms as you may get attemping to play different formats.
Also, check the tape edge (press button on side to release and raise protective flap), for signs of tape damage. Sound and synchronization information is encoded along the edge of the tape. If it's damaged, it's not repairable.
Cobweb
October 2004