Upgrade to 5.4a, main window no longer displayed

I just upgraded to 5.4a (it had been a while since I last upgraded, so I’m not sure what version I was running before). The setup and installation appeared to work correctly, but I now cannot get the main window to display at all. It looks like it has set its position to be off the screen, but I can’t figure out how to move it. I opened up the registry, and the Ifaceleft and Ifacetop values in misc seemed pretty high if they are the position (5932 and 6218 respectively). Playing with these values looked like it was changing the position (judging by the XP minimizing animations that appear on the screen after every other click of the tray icon- they move around). However, I still cant get the window to display. Deleting these values doesnt help either- they default to the (possibly) high numbers. Any ideas?