i need a user (a Secretary) to be able to remotely shutdown certain computers.

she is not in the local administrators group or power users group on her regular computer or the remote computers.

how do i go about being able to let her remotely shutdown these computers?

i have a batch file on her desktop.

shutdown -s -m \\desk1
shutdown -s -m \\desk2

i would like to not add her to the local admin group of either computer if possible.

Open secpol.msc from the run menu. Browse to Security Settings\Local Policies\User Rights Assignment, and find "Force shutdown from a remote system". If you add the secretary to this policy, then she will be allowed to shut down the computer. You need to make the policy change on desk1 and desk2, not the computer which the batch file is being run from. Also, make sure that her username and password are the same on the target computers as on the computer launching the shutdown. If you are on an active directory domain, then this isn't a problem and you can just change it in the default policy, or add the policy on those specific machines for her domain account. If you aren't on an AD domain, then you'll have to make sure her username and password are consistent.

you could also script that command to run as administrator using runasspc. it allows you to embed an administrators password in and encrypted form.

http://www.robotronic.de/runasspc/