Can I legally install a single purchased copy of WOFF twice, once my own PC where it has always been. And another copy of the same purchased copy on my own gaming laptop?

Yes, WOFF3 does not require a serial number and WOFF UE has one that has no limits, i.e. I have WOFF UE on both my gaming desktop and laptop at the same time.

You can install on more than PC but must be for your own personal use only.

Not entirely OT: Coming back again, with some holidays in view - do we still need the CFS3 original CD ?

Only for WOFF 1-3, not for WOFF UE.

Yep no need for the CFS3 disk for UE.

Thanks a lot , i know i have this CD somewhere in the attic, but ...

I see the old crew is still strong, too !