I`m I understanding that u want to take u`r existing 80g drive, which has an 80g windo$e partition on it, and make a 60g (retaining the old windo$e) and add a 20g for u`r visa ?
If I were to do this, I`d firstly backup my crucial shizzle (for fear it may screw up), then use something like PartitionMagic to attempt a resize of the partition.
I know you can make the partition bigger and retain the data. But I`ve never tried making it smaller - I`d ~asume~ u can coz I think the tool option is "Resize".
Then obviously make a new 20g.
Probably be a faster process if u make sure u`r defragged as much as physically possible, so if PM does it`s resizing it hits as little a quantity of files as possible.
If I remember rightly, I may have used Ghost to make a file listable backup of a partition, scrub the partition, make a new partition, then Ghost the files back, I`m just not clear on whether this worked well or not.