Help wtih web page opening

Ok so ive done a few days of searching for the answer and it is eluding me. Whenever i try to open a page with a .xml extension it just opens the source code in wordpad. I tried switching the file association to IE no luck then just nothing happens. I use IE7 on Vista Home Premium. If anyone has any idea's to try im all ears. Basically the problem is that .xml stuff wont render into a web page.

Edit: They open fine in firefox so it is def some problem with IE that is bugging me that i would like to fix.

Thanks for any help

Ok i worded the problem wrong when i try to open worldofwarcraft.com i get a msg to open save or cancel index.xml it only happens in IE7 the page opens fine in firefox as i said. I dont even know why the browser would be doing this when i try to open the page. If i choose to open option i get the raw data in wordpad. Save lets me save it obviuosly. But i cannot open the page itself as a web page. I am just lost as to why it is doing this at all as you said xml is raw data.

I am stuck here and dont really feel llike doing a clean OS install so early but looks like ill have to since there is no real way to reinstall/uninstall IE7 in vista since its integrated so much :( MS def sucks sometimes.