I pulled my battery out like I always do to switch the battery. And when it rebooted I got a really old school looking version of the blackberry OS (all black and white and no background). It still prompts me to put in my password at the startup but after that it gives me a uncaught exception message saying: java.lang.NullPointeException. I press ok and most everything doesnt work. Including the phone. I plug it in to my pc to perhaps try and restore it but bb desktop wont connect to it...it detects but wont connect. does this mean warranty replacement or is there a hassle free diy fix.

When it boots into the black/white screen can you find a swiss army knife icon (that would be Options) and scroll down to "Theme." See if you can choose a theme.

well theres no icons either...i went to theme and it gave me another error message. forgot what that one said. and it wont let me chose any other theme....its set on "none(active)"

And you're sure you did NOTHING but pull the battery? It sounds like something got removed from the BB. You're going to have to wipe the device and reload the OS. Can you plug it in and make a backup of your data using Desktop Manager? Either way, follow the following instructions:

How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ

Is your OS version 4.2.2.123?