acoo

I have Acoo Browser And Opera in my comp. I have set Acoo as default. But now i wanna change it to Opera. If i change it, opera becomes default when i press the www button on my KB. But if any app wants to open browser, it opens IE. What to do? Opera is my fav.

My firefox freezes frequently with a XP error msg with a send/don't send button. What is the problem? But when i restart my computer it works. IE and ACOO don't freeze.