im sure many of you already know how to do this but for those who dont. if you try to update your bb software to the 4.5 you may get a fatal error where you dont have an os this can happen with any software ver. update you attempt to install. what you need to do is "downgrade" your software back to the one you had before. its always smart to have the prevoius ver of bb software on a jump drive or some wher on your comp.here are the steps.
1.) delete the new version of the bb os from your comp
2.) install the old versions of the bb os onto your comp
3.) install the new version of the bb os onto you phone via the apploader.