A. Background for those unfamiliar with Unix: It is a good idea for system administrators to do everyday's work with a low privileged account and only change to an account which is a member of the Administrators group if you really have to do administrative work. To avoid closing all open applications and log off, it is useful to have a utility that allows you to temporarily start applications running in the security context of a different account.
The Resource Kits ships SU.EXE, a free equivalent is SU.ZIP (on Cica in /admin). Both require setting system privileges for the caller. An alternative is SUSRV.ZIP (also from Cica), which has to be installed as a service, but does not require privileges. There is no equivalence to Unix suid programs (i.e. a file attribute which achieves that the file is run in the security context of the owner instead of the caller, without specifying a password).
A new utility is NTsu which will allow you to run programs in the security context of any user in your system or domain. NTsu also allow you to have multiple desktop's, each one for a different user, and you can switch from one to another. NTsu is FreeWare. It can be downloaded from http://32bit.bhs.com or http://www.ntfaq.com/ntfaq/download/ntsu10.zip. The official page is at http://www.teleline.es/personal/quimeras/ntsu/ntsu.htm
Windows 2000 now supplies RUNAS.EXE which allows a program to run as another user (see 'How can I run a program as another user in Windows 2000?' for more information).
