In POL, use the Configure menu to start a Command prompt on this drive. CD to C:\KDE4 and run the installer.
Choose for a start maybe just on or so applications you like and continue. For me it installed 80 to 90 packages, which takes a while. If it "hangs", just cancel an start it again - fortunately it keeps the already downloaded packages.
After finishing the install, still from command prompt (or you can start it again maybe), do the following commands:
C: cd Program Files cd KDE cd bin dbus-env.bat dbus-launch kdeinit4 plasma-desktop