Sony Ericsson C510 wont turn on?

I have a Sony Ericsson C510, and it was working fine up until I got a message saying something like 'Incoming text message. Not enough space to Store. Delete files now?' I pressed OK, and it immediatley turned itself off. Now whenever I turn it on, I get the usual Sony Ericsson logo, then just a black screen, which flashes every couple of minutes. Can anyone help, PLEASE??!!!! I've tried to connect it to my laptop to update it but it isnt detected by the laptop anymore