You might do better asking in the Opera forums, where there are many more Opera users: click here
See this knowledge base article: click here
Is the feeze happening on a specific website? If so, provide a link for others to test.
Duplicate plugins can often cause problems. Type opera:plugins in the URL field to see what is installed.
I find that many intractable problems are resolved by deleting opera6.ini in the \profile\ folder after closing Opera. If you know what settings you have changed, it doesn't take long to select them all again. Or just move opera6.ini to C:\TEMP\ so that you can undo the change if it doesn't help.