Thank you Henry & Tim,
but I already have the full version, and it's easier and cheaper simply to avoid the advanced functions! After all, 'Word' and 'Excel' offer much more than I need.
(I have just finished an 'Excel' spread-sheet helping me adapt a published drawing set to suit my own project, whose GA is in vague progress in TurboCAD. It converts the given vulgar-fractional dimensions to decimals, in inches. I've also used 'Word' and 'Excel' for my alphabetical index to TurboCAD's Manual.)
When I thought TC had developed a fault two or three weeks ago, I removed and re-loaded it, from the CD, whereupon it treated itself to some up-dates - I don't know their identities but they took some time to embed themselves
I had bought the programme knowing it has isometric and related capabilities very useful to me; but not knowing even basic 3D drawing that is fairly simple manually, is extremely difficult in CAD. However, by keeping the edition I have, that aspect of TurboCAD is still there if I wish to risk it again.
Murray - re your explanation, for which thank-you. I understand Polar and Cartesian Co-ordinates having created umpteen graphs in both, professionally, but I'm afraid you rather lost me with TurboCAD's assorted co-ordinate systems. Normally, when I start a new drawing I play safe and use only the default co-ordinates, work-plane and layers, so if I'd changed any of their settings, it was by untraceable accident.