Not necessarily a fault, try this first...
If the VCR is connected to yout Television's AV input, check on Television that you haven't inadvertently switched it's connection to S-VHS (your user manual will advise).
Alternatively, if there is a spare AV connection on the TV try it on that one instead, if colour returns, it's likely the other socket is switched to S-VHS.
Cobweb, January 2005