The responses in this thread left be baffled.
All I did was install SU, copy the "Google SketchUp 6" directory from "C:\Program Files\Google" to the USB drive. Take it to the new PC and run the "SketchUp.exe" file.
The only plugin that complained was IDX renderer but I just Ok the error message and everything else works fine.
I only use the free version but I don't think that it has a problem opening models produced by the Pro version.