IE9 and Vista – Why are there so many problems here?

This combination has been giving me headaches. Pages stopped responding, links didnt function, pics didnt open.
So, I followed the MS advice and permanently activated the compatibility mode for all pages. Much better, but….
I still have numerous glitches and slow downs and the occassional links still dont function.
What, if anything can I do about this to improve the situation?
What would happen if I put this IE9 on a WINXP system?
PS – I had just wanted to send this with IE9, and guess what – the button did not work. So, if you are reading this, my new FIREFOX works!