Try this:
HTML Code:
<form action="search.php" method="post">
<div class="smallfont"><input type="hidden" name="do" value="process" /><input type="hidden" name="searchthread" value="1" /><input type="hidden" name="showposts" value="1" /><input type="hidden" name="threadid" value="361" /><strong>search for a video</strong>:<br />
<input type="text" class="bginput" name="query" size="20" style="width:175px" />$gobutton<br />
</div>
</form>