Windows XP & Java?

[flapsforty]

The PC I use when at my home-away-from-home, has last week been spruced up by it's owner. He installed windows XP.
Browser is a newish IE, I think.

When I try to get onto pprune chat, I get a message about "The current version of XP not being able to download a Virtual Machine due to a court case".

I am totally stumped by the whole thing, have tried reading all the web pages microsoft links to with regard to this, but the end result is still no chat.
Anyone can help here?
(whole PC was reformatted and if I understand that concept correctly that means that there are no old bits of file that can cause this problem)
Many thanks in advance!