There are two things we can suggest for this:


1) In the folder "C:\Program Files\InstallShield Installation Information" folder, delete the subfolder "{E376D45C-2C25-4437-9FDE-CEA857BF1DE9}" if it exists

2) Delete the registry key "HKEY_LOCAL_MACHINE\Software\VCOM\WebEasy Professional\5.0.0".


Doing one or both of the above should allow you to re-install.