I know that worksheets saved in Prime 7 cannot be read in Prime 6 (or 5 or 4 ...). I also know that from Prime 7 you cannot save a file in Prime 6 (or 5, or 4...) format. I guess PTC wants all their Prime customers to use (only) the latest version of the software.
I do not know if your license allows you to install the software on two different machines, I would guess not. PTC is happy to take money.
I remember reading that a license for a version of Prime will allow to run that version and any preceding versions of Prime. So with the license for Prime 7 on your laptop, you should also be capable of running Prime6 on that same laptop (the license file is generally tied to the network MAC address). So I think that you can install Prime6 on your laptop, to run in full, but it's a bit tricky. Prime versions must generally be installed in version order. So you have to (have) Prime 6 installed before Prime 7. If that's your case, then you can make use fo the procedure described here to create a Prime6 file from your Prime7 file using your laptop. Then subsequently make only use of Prime6 on both machine, or decide that you will throw another donation into the PTC money pit, to get a second license.
Success!
Luc
