Blackberry 8320 won't switch on please help?

[franceds]

I've got a Blackberry Curve 8320 and I was doing an update on blackberry desktop manager then suddenly my usb came off and some error came and whever I try to turn on my blackberry the red light keeps blinking and whever I plug my usb to the computer it comes as unkown device. Is my blackberry completely dead? Btw I can't connect it to the computer and I've tried pulling out the battery.
Can somebody help me please?

Thank you

btw im from the uk and I have tried pulling out the battery and putting it back in numerous times and also the charging and taking out the battery then turnin on all didn't work.

THE STUPID LIGHT KEEPS FLASHING!!!!

Anyone know how to fix this?