I frequently need to swap one file with another, without overwriting the original.

Let's say there are two files, foo_new.dll and foo.dll. I usually rename them the follwing way:

1. foo.dll -> foo_old.dll,
2. foo_new.dll -> foo.dll,
3. [do something with replaced file],
4. foo.dll -> foo_new.dll,
5. foo_old.dll -> foo.dll.

This is ok for a single file to swap but it becomes tedious when swapping multiple files at once.

Is there a Windows (7 and preferrably XP) utility or a technique that simplifies this task and works well when swapping multiple files?

I'd prefer to be able to use it from within FreeCommander but Windows Explorer would be ok, too.