I just sold my 7100T and have gotten it unlocked by T-Mobile. I would now like to erase all data on it including my addressbook, saved user namd and password for IM etc. How do I do this?
Use JL_cmdr (search for it on the forum, it was authored by a member). It is a graphical front-end for the javaloader.exe that is the management utility for Blackberry developers. There is an option (5) to wipe the handheld. Once you have done this, just use the desktop manager software to reload the OS (download from the orginal phone provider).
another option is to use the Desktop manager, go to load, uncheck everything, go to advanced, "don't backup", and "completely erase".
One more is to download the blackberry development environment and use the javaloader.exe -usbwipe from that.
Any of these methods will erase the bberry completely. I strongly recommend the JL_Cmdr for speed and ease of use.