5.4b main window size is 0,0 ?

I installed 5.4b over 5.4a afterwwards the main window will not display. It appears to have a size of 0,0 the window bar will animate as you close it by double clicking the icon, but no window ever appears. The right click icon menu fails to work also. I tried uninstalling and reinstalling. Deleting all of the registry keys I could find after uninstalling, rebooting and installing again all without any effect. help