have a problem trying to open boot on vauxhall vectra 1.8 p reg?

have a problem opening boot on vauxhall vectra 1.8 p reg. 1996? read manuel but the instruction that it gives doesnt work. all other doors and windows work with the key fob but the boot refuses to open. have tried to open with the key but that doesn't work either. even tried to get at the lock in the back of the car , nothing. it seems like an electrical problem.had the car at my local garage over weekend to fix new brake pads etc, and although it sounds bizarre it was fine before that?? any answers??