What is wrong with my worcester 28CDi boiler?

I have a (very old) Worcester 28CDi boiler, which until this morning was running perfectly! However, tonight I discover that I do not have any hot water. The heating works perfectly (fingers still crossed!) but there is no hot water coming from the taps. I have checked the pressure of the boiler and filled to the required level. I have also bled the radiators (in the sequence required) but still no hot water...........please help, I have been painting all day and in desperate need of a long, hot, soak in the bath! many, many thanks! xg