On the thread 'Filevault. How good?' I briefly detailed what I've done recently, involving upgrading from 10.6.8 to 10.8.

This was mainly to access increased security on the later OS.

I've coped with the odd problem, but now a Major One has arisen.

It won't let me open Quark Passport 7!

So if I go forward, I've got to buy upgrades to 8, and from discussions I've seen on the web, probably a full upgrade (expensive) to 9.

Hence the question. Can I de-install 10.8 and reinstall my original 10.6 OS, so that I can carry on as I was a couple of days ago?

HELP wanted.