Thanks debro for responding.
I wish to report that I have achieved what Bob originally requested.
I have two drives (60GB and 30 GB)
I disconnected one and used W98SE Dos floppy to format the drive (used Fat32).
I then used the floppy to install W98SE
I then used XP Pro CD to replace W98 with XP
Installed SP1 then SP2
(Probably SP2 could have gone in without SP1, but I was not intending to put SP2 intil I noticed some app problems that needed SP2)
Turned off Swap File, and turned off System Restore.
I disconnected that drive and did the identical process with the other drive.
I then connected both and booted into one of them.
I could see the other but I could not boot into it.
Fiddled around a bit in the Bios menu pointing it to Master/Slave (or whatever).
Then went to the Boot order in the Bios menu.
Only one of the 4 lines(floppy, cd, etc) would recognise the drives, but that one would let me choose which one I wanted to boot into.
Thus any time I wish to boot into the other drive, I just catch the Bios menu, and choose which of the drives I want.
I boot into the 60 and copy all the files/folders in the 30, into a Folder in the 60GB drive. I also burn that to a DVD.
I then restart the computer and boot into the 30 and do the same exercise.
I can now boot into say the 30, and try out programs etc.
If I get into a mess, and want to 'go back in time', I boot into the 60, and delete all the files/folders in the 30. (NB I do not reformat)
I then copy the snapshot from a healthier time in the past.
All that takes about 5 minutes, and when I boot into the 30, it is all clean again.
The same exercise can be done in the opposite direction, if one chooses.
I think this achieves all of Bob's wishes (not to mention my wishes).
The swap file may not have to be switched off, but mine has stayed off.
(I have ordered more memory.)
I do believe that the System Restore should be left OFF permanently, when you are doing what I have described.
My two reasons are -
a) This is a far better restore process.
b) The 'cross talking' that I was worried about, definately happens if you have System Restore switched on.