[fizzwheel]

bit more info as to what happens when you press the start button would be useful.

I.e do the dash lights dim, does the rev counter needle spin round the dial, is there a buzzing / clicking coming from somewhere near the riders seat.

If all or some of the above then I'd suggest a flat battery. But you'll need to identify the cause of the flat battery before you go and splash out on a new battery IMHO.