Thanks so much for the help.!
What the Rudge and Aherkey have said is quite true, but I thought you were asking if you could have 2 different operating systems in 2 different partitions? So that you have e.g. kde4 in partition 'A' and gnome in partition 'B'?
I did that before. I had kde3 and lxde in different partition, one backing up the other so that in case my tweaks ruined the first one, and it could not start, i could still do other
things from the second operating system until I figured out what went wrong in the first one.....to have minimal down time......
(I had /Home in partition 'C' and broken windows and glasses in partition 'D', well just to remind myself of the jagged edges out there
Have not got around to doing it again. But I still plan to have kde4 together with gnome. Or lxde. Or e17...Drat. Too much choice.....
I might need help here