I have reinstalled Mageia 3, 64 bit in order to switch Desktop from Gnome to KDE. Some issues arose;
I selected Install (but not update),
Use existing partitions,
And don't format any partitons.
The installation attempts to find what is installed but usually does not progress even when left for more than 2 hours So I turned the computer off and on. On one previous occasion it did proceed and after 15 minutes and I was able to continue installation.
I selected; Custom; KDE, Gnome and LXDE.
The installation proceeds to update packages with dialogue box periodically asking for my consent.
But it apears to have completed ask that I remove installaion media and restart the computer But I did not do that straight way (I was doing something else) as I had done before and another request poped up which I consented to.
Significantly I think that extra installations have resulted in a slightly better performing Linux installation.
Speciffically I found that previously when I switched to LXDE and I accepted an update then Gnome was removed but this has not occured on this occasion.