This is what the search page looks like for me right now (I'm on Mac, with Firefox 3.6.13 )...
Comparing that to https://stackoverflow.com/search, it seems that the search box has pushed the main instructions down.
Also, the search boxes ought to be shrunk to allow the longer search button names. (They are much shorter in Chrome and therefore fit fine, which seems to be because they are using the
size attribute. Should they be using a pixel width instead?)
The float problem is the same in Chrome.