XP root

it seems that in a muilti-user enviroment, dues to security, not all users get access to C:\

this is often the case at colleges, etc.

if that is the case, what is the shallowest folder users can get to, and how could that be determined at runtime?

Is there a parent folder in that situation, or are individual sister folders allowed on an arbitrary basis here-and-there?

how might one iterate all folders available to read for a restricted user?

any and all replies welcome, and needed.
thanks

In most of the cases any users can access windows temp folder like C:\Windows\Temp or C:\Documents and Settings\<username>\Local Settings\Temp\