I have been having this problem since the end of July.
When pressing the "search" function, nothing happens. The problem seems to be Windows XP. I usually use a laptop that is running XP to view AVS. When I use a machine running Windows 7, everything works as it should.
However, with XP, the search function is not operational and things like mouse hover to view hidden text (such as hovering over a thread title to reveal the full title, etc) no longer works.
I've tried both firefox and IE with the same results.
Again, the issues started toward the end of July. Was there an update to AVS at that time that would explain the issues? I do not have any of these usability issues on other websites/forums/etc.