1. Open Control Panel
2. Click Add or Remove Programs
3. When the list of installed programs comes up, look for Java Runtime Eviroment or Java Web Start or something of the sort.
If you find it, that means you have it, lol.
To turn it on or see if it is turned on, if you found Web Start, look for that folder on your All Programs list on the Start Menu
Open it. Go File, Prefrences. Click the Java tab, and enable it by clicking the checkbox.
If you can't find it, you might not have it, so go to http://java.sun.com , download and install.
Xander