Help Unrooted HTC Desire S (3 Network, Gingerbread 2.1) - Won't Boot - Can't Factory Reset Either



Hopefully someone can help. A couple of months ago my unrooted Desire S froze, and when restarted went into a continous booting cycle. To fix I did a Factory Reset and this solved the problem.

Yesterday the phone froze again, I took the battery out and now it won't boot past the initial '3' mobile welcome screen - it just stays on this screen permanently.

I tried to factory reset again, but this time after I've powered on/held down volume, I can scroll down to 'Factory Reset', hit the power on button but it then it just freezes.

I'd rather not have to leave it in the hands of 3 customer services, so is there anything else I can try myself with it in the state it's in?

I'm fairly techy, but this has never extended to rooting phones etc.

Any help appreciated.