Hmmm, thanks for tips, it does seem however that how you store them will depend on the likelyhood of them working or not. The ones I had in a proper sealed disk box work fine, the ones in the cardboard box / plastic bag look like they have died over time. In fact I can go further and say the ones in the box were kept in the house where as the others in the garage, so possible issue there.
As to what I have lost, well mostly PD demos but worst was some of my old Amos Pro projects, nothing major but a shame all the same.
Andy