Get the latest version of SimPE from Sourceforge.
To reset the display
Go to "Extra" then "Preferences." In the "Preferences" pop-up, go to "SimPE Settings" and click the "reset Layout" button. If worse comes to worst, you could uninstall SimPE then reinstall it. This should reset everything back to "factory settings".
solution to reset the positions of the windows to their defaults without uninstalling and reinstalling SimPE.
First close SimPE, then open up Windows Explorer and go to your SimPE installation directory, go to the folder 'Data' and delete the following 2 files
layout2.xreg & simpe.layout
These files will be regenerated once you reload SimPE and the windows in SimPE will be in their default locations.