I am transitioning from 32bit to 64bit PC setups, new laptop is running 64bit win 7. Old desktops are running XP 32bit (Pent D, 2 gb RAM) and Vista 32 bit (Core 2 Quad, 4gb ram).

Since I would like to be able to use files between them, can I create a partition on the C:'s of both older desktops, install win 7 64 bit on them and so be able to use 64 bit files on all if needed?

Would it affect current 32bit XP and Vista installs or can it be done now without stuffing up anything?

Since I do a bit of rendering work, it is great to be able to use another PC whilst one is rendering but I dont want to be stuck with incompatible versions between 32 bit and 64 bit files but have many oppurtunities where a job will stay on just the 1 PC and I would like to take advantage of the extra ram and speed of a 64bit render in those situations.

I can install 32bit software on 64bit correct? Just not in reverse. Also I need the older setups to stay for some oder equipment so wiping out the 32bit installs all together is no good.

So ina nutshell is it possible to add a dual boot system with 32bit and 64 bit operating systems without affecting the original OS's or would that have to be done with complete fresh installs of both?