Do this first:
How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ
If that doesn't work, do this:
What to do next if Jl Cmder will not connect and wipe - BlackBerryFAQ
If you can do one of the above get the most up to date OS from here and follow the instructions:
http://www.blackberryforums.com/gene...ilanguage.html
If none of that will work, then time to get it replaced. I'd be quite suspect anyway as the device shouldn't have done that unless you loaded some 3rd party application that doesn't agree with it.