First things first. "Reset your BlackBerry" is a bit of an ambiguous term; it can have quite a few different meanings. It all really depends on what you want to do with your BlackBerry. Resetting your BlackBerry can be as simple as performing a soft reset or a battery pull. Both will restart your smartphone, hopefully fixing whatever issue you're experiencing. A much more invasive type of reset is a the complete wipe of your phone's data and operating system, using a third-party program on your computer. There's also the option of the Security Wipe. Beware with the security wipe, you could end up losing all of the data on your phone and memory cards.
Somewhere in between a battery pull and a security wipe is the option to complete a Factory Reset. Using BlackBerry Desktop Software (or some command line...er, commands), you can reset all of the settings on your device to their "factory" defaults. And no, this option doesn't return your BlackBerry to the way it was when it left the manufacturer. I checked. After the factory reset, I was still running the same version of the operating system as before and not the one the device shipped with.
Like the security wipe, this type of reset will also remove any lingering IT policies from the days when your BlackBerry might have been connected to a BES. Unlike the security wipe, it leaves all of your applications still installed. All of the settings and such for the applications will be wiped out, but at least they don't have to be reinstalled.
Warning! Bad things can happen!
