Java and Firefox

[Ancient Observer]

Win 7/64 home prem. Firefox 15.0.1. Signed in as guest, not admin.

Firefox has said a number of times in the past that it doesn't like the Java on my machine, and won't work with it. That's fine. However, if I downloaded java afresh, Firefox has normally worked with it.

15.0.1 will not work with it.
I downloaded both 32 and 64 bit java, afresh, but sites that need java just will not work with my 15.0.1. (An e.g. is the BT speedtester site)
I really do not mind, as I just switch to IE . (9 appeared of its own volition, so it is IE9)
Should I be concerned, or just carry on switching as nec.?

[Ancient Observer]

Yup, and Ghostery, both recommended here....

[Ancient Observer]

OK, will do, (unless it is tooooo complicated). thanks.

[Gertrude the Wombat]

This is all rather a pain, particularly when you need a particular version of Java because your client insists that that's what you do the development with, and today's newly patched Firefox starts throwing a hissy fit.

There are ways of telling Firefox "shut up, I know what I'm doing, just let me get on with earning a living" but the explanations I've found are a bit random, and last time it happened to me I tried several things round in circles until at some point for some unidentified reason Firefox started behaving in a sane fashion again.