I think it was earlier in the year I looked through the FireFox site's release pages and bug reports. I believe there are still bugs with both of the most recent release versions of FireFox, especially the most recent. I do not have the most recent version and decided not to after reading their reports but that was a while ago now. I did not like everything about the version I have now as it were (I have v.5.) Updating is not always for the better it seems.

It is my guess you have come across a bug with the most recent FireFox version, perhaps related to earlier Windows operating systems or perhaps even due to the version of Java you have combined with the mix. No idea.

The symptoms you give are definitely an incompatibility of some kind. Video card or Java combined with FireFox. One suggestion might be to try to downgrade to the next down Firefox version. But that in itself may cause some headaches with support files.