Welcome to the forums!
If you have the 8100, download and install the latest official release of 4.5 sticked at the top of this board. Going from 4.2 to 4.5 is like getting a new phone.Just be sure to follow all the istructions. Also, be sure to check out John Clarks memory optimization thread ...
http://www.blackberryforums.com/gene...ee-memory.html