New to Java

I recently added a P2P program (eTomi pro) that relies on Java. My laptop is now running very hot now, to the point where the fan kicks in, which I've never known it to do. I also get a java.exe warning message in the shutdown sequence.

I'm a computer luddite, but knew enough to find out it there's a better version available. I see that I have two folder in Java:

j2re1.4.0_03

j2re1.4.1_02

which I assume correspond to the verson numbers.

I see that there is a 1.4.2 available, but when I went to download it, I had to choose between the Netbeans version and a J2EE4.2 version.

Which one of these should I download? Or is there an update function somewhere?

Also, can I then safely delete the older versions, is there an uninstaller for them, and generally how can I get rid of the older stuff?

(I'm running Windows XP on a Dell Inspiron and use it pretty much only for wordprocessing, internet stuff, iTunes, and now this P2P stuff)

Thanks, and sorry if this is too basic for this forum, but I don't know where else to ask.