If you look at the cassette's "spine" (the edge where a long thin label would be placed) you'll see a plastic tooth to the left of where the lable would be. This Record Tab is designed so that if you break it off, you cannot record on the VHS tape again. You may find that your cassette does not have a record tab. Try comparing your blank tapes to pre-recorded tapes you have bought.
If you do need to record on a cassette which has had the Record Tab removed, stick a bit of tape over the whole where the Record Tab is. Your VHS Recorded will record on the cassette again.
Andrew, March 2005
