BB 9000 Bold error and now rebooting (loop)

hi, guys!
i have a blackberry bold 9000, bought it 4 1/2 years ago. worked well a looong time. i wiped it a few weeks ago and installed os 5.0..... the newest one aviable (i think, it's the 1147) with the bb desktop software and i installed the newest whatsapp and the opera mini browser. nothing else. worked well so far. some days ago i checked my messages and got an error on a white screen: 371 (or 317. i dont quite remember, but i think 371). it restarted automatically and the error appeared again. and again. and again. i couldnt do anything else but pulling the battery. after i had waited a few seconds i put it back in and it booted. but since then the bold has stayed in another rebooting loop: red led lights up, it seems the bold is loading for about 60 secs (black screen) and after this it resets and the whole process starts again. windows and the applauncher recognise the device (windows usb connecting sounds and bb pin number), but i cant get any kind of connection to it. i really tried every possible way of wiping, resetting, updating, battery pulling etc. by updating with the apploader it stops at the point of reconnecting to the jvm: the bolds starts the loop and the software tells me it cant connect to the device. i have now clue what's wrong and i dont know what else i can do... though... if there's nobody around who could help me, i'll have to throw it away. :/

greetz