AD user/computer policy confusion

If you want all students........as opposed to all users........to have a particular policy, you would put those user's in their own OU and enable the settings in the group policy object associated with that OU.....if you want to apply to all users, you would set the policy at the domain level.

Similarly, if you want to apply policy to a computer...ie all users logging into that machine.....you can also do so for all computers at the "computers" OU level or you can put some machines (for instance, the accounting dept machines) in thier own OU and apply policy just to them.

The main difference is.....do I want to apply the policy to all users who log into particular machines.....in which case you would apply the policy to computers rather than users
or
do I want to apply the policy to particular users, no matter which machine they log in to......in which case you would apply the policy to the users

Note that some policy settings only apply to computers and some settings only apply to users.

And to anwer your question directly :-)   .........you would put the students in one ou, apply your desktop policy to them at the ou level.........but leave teachers and staff in the "users" ou with no policies restricting thier desktops......unless you want to annoy *everyone*, of course...........

so if a user is a member of OU X, and they logon to OU Y... does their X policy go into effect or the Y policy of the computer?

Answered, in more detail than asked for.