Think back - what windows or applications were on your screen, what keys did you press, what did you click on or what did you drag?

For me the easiest thing to do would be in windows explorer, in the MyDocuments\LDW folder, I would click once on the Plant Tycoon folder, then type Control-C (copies it), then type Control-V (pastes it) which would create a new folder called Copy of Plant Tycoon. Every few days I would do this again. Future copies would be named by the computer "Copy (2) of Plant Tycoon" and "Copy (3) of Plant Tycoon" etc.

If something went wrong with game 3, I could find Plant Tycoon3.ldw in one of the backup folders, click on it once, press control-C to copy it, then go to the real Plant Tycoon folder, click on Plant Tycoon3.ldw once, then click on the name once so it is highlighted, change its name to Plant Tycoon3OLD.ldw, press enter or click in the white area to make the change permanent, then click control-V to copy the backup version to this folder, and that should do it.