Are you sure the battery is not dead? If there's doubt, you should plug the device into a wall charger for a little while. Then while still plugged in, remove the battery for a few moments and replace. If that doesn't get you, then see the following: How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ
Wipe the device. That will leave you with the 507 error (no operating systen). Then reinstall the operating system. (See the sticky latest OS threads and look at the one for your model blackberry. Or install the OS version provided by your carrier.
I have no clue what happened to you or how to prevent it happening again. Take things slow and follow directions exactly. Let things finish and do not interrupt or disconnect until you see confirmations.
Good luck. Posted via BlackBerryForums.com Mobile