I have a 6300 Hp Scanner.  The software went screwy a year or so ago, and the workaround was to open the software do a ctrl-spacebar (I think that is right) and a minimized icon would appear.  maximize the icon, and you could use the software.

I have now downloaded an upgraded version of the software, and no longer have to do that.

Could it be possible you might have a newer version of your software that could be downloaded from the Hp site?