OK, here's how I have implemented security templates throughout an organization
1. create a new OU and name it something like Secure Workstation
2. move all computer accounts into this OU that you want to have high security applied to (or just a couple first for testing)
3. Right-click the new OU and click on properties, then click on Group Policy tab.
4. Click on new, and then name the new Group Policy, something like High Secure Workstation Policy. Then click on edit.
5. Under Computer Configuration, expand the Windows Settings.
6. Right-click Security Seetings and click on Import Policy
7. Choose the template you want to import (highsecws.inf)and click open.
This will import the template, and make the security changes for the group policy. Move any computer accounts into this OU that you want to be secure (if not already done), and that should do the trick. Remeber, it's important to create a new OU for this, just so your not affecting the default group policy, in case you get undesired results. Reboot your workstations, or wait/enforce group policy.
And a couple usefull sites regarding 2000 security templates...
http://is-it-true.org/nt/nt2000/atips/atips74.shtml
http://www.microsoft.com/windows2000/techinfo/planning/security/secconfsteps.asp
http://www.brienposey.com/kb/working_with_windows_2000_security_templates,_part_1.asp
Hope this helps...