Ok hope someone can help... last week my 7280 started to act up.. as i was typing the red led light turned on and the bb restarted itself. Then i got a 507 message.. i tried to correct it , and didn't get lucky. Today I sent it to my carrier, and they updated the OS system and my blackberry was back to work, I charged it and then ,when fully charged, started to use it, it was all normal.. until suddenly when I try to reply messages and begin typing it shuts down and reboots. I recently lost my wall-charger, and began pc-charging. don't know if this is related?
What can I do?

HEY I SEARCHED AT ANOTHER FORUM AND FOUND THAT SOMETIMES THE BATTERY GETS A LITTLE LOOSE, AND IT MOVES ,SHUTTING THE BB DOWN.. SO I PUT SOME SCOTCH IN IT, AND MOVE IT AROUND, TYPED AND ALL THAT. ITS PERFECT NOW!.