Java is definitely installed on this system and in the past has worked fine. I have the following folders in my Program Files\Java folder:
I can't find it under my Add/Remove Programs list, however, and if I try to upgrade or install the newest version of Java I get an error that says "To restart the Java installer, please refresh the web page." I tried the manual/offline installers and when I run them, nothing happens at all: the process briefly appears in Task Manager and then immediately disappears.
I'm not sure what's going on but it's really getting annoying. This is on a Windows XP SP 2 machine.