Getting to be off-topic for the Cygwin list, but here's a pointer:
<http://google.com/search?q=rename+%22documents+and+settings%22+directory+site%3Amicrosoft.com>
In particular, the first and fourth hits look relevant.
As for "Program Files", as far as I know, the name isn't special in any
way -- you can just rename it (and, of course, move all the programs
already installed there - yuk!), or, better yet, simply don't install
Cygwin under it... Plus (to get this back on-topic), you can use Cygwin
mounts to hide the spaces in directory names, e.g., on my machine:
$ mount | grep java
c:\Program Files\IBM\Java14 on /usr/contrib/java type user (binmode)
HTH,
Igor