Renault Clio 1.2 16v 2002 won't turn over

Hi folks i bought a Renault Clio 1.2 16v 2002 a couple of days ago it's got 59000 miles on it and runs beautifully. A couple of days ago a light came on (a zig zag with a coil) and I was driving for about an hour then turned the engine off, when returning to the car i tried to restart it and it didn't even make a noise it was completely dead! So I rolled it a little bit with the intention of bumping it but the power came back on as soon as I rolled it. Once again it drives perfectly when it starts, it's just when I turn it off it sometimes doesn't respond atall Does anyone have any idea what's wrong if so please help!

Thanks