Hi folks.
You can probably save the uninstall and reinstall of SU 8 with this trick:
Rename the "Google SketchUp 8" folder. Use "SU 8" for example or just add -1 or whatever to change its name.
Install SU 7. Normally it should install in a separate directory.
When done, rename the SU 8 directory to its former name.
You now have both versions available.
Just ideas.