Well, while trying to solve my own Java issues, I noticed a lot of people were having problems if they also had Microsoft Java Virtual Machine installed along side Sun Java. I believe it was released on XP from 2001 to 2003, then Sun stepped in and filed a lawsuit. You can also choose whether an application opens in Virtual Machine or Sun runtime environment, though I couldn't tell you how to go about that. Sorry, I'm having serious issues with Java. I can't even open the control panel.

But, you can go here:
http://javatester.org/version.html
...to find out what version you're running.

More information on MSJVM:
http://www.microsoft.com/mscorp/java/

Yet more info on MSJVM:
http://www.theeldergeek.com/java_virtual_machine.htm

And, if you like, you can install MSJVM if it's not already on your PC. If anyone does this and it solves their problem, please let me know. It looks like 3rd party stuff. I'm not endorsing them...
http://java-virtual-machine.net/download.html