Hi there grwrogs,
Right click on My Computer, and click on Manage.
Click on the + next to Users and Groups
Click on the Users Folder.
On the right side of the management console, Right click on the user account
that you wish to put into the Administrators group.
Click on Properties.
Click on the Member Of tab.
Click on the Add button.
In the box mark "Enter the object names to select", type Administrators.
Click the check names button.
Click OK.
In the member of listing, Highlight the groups that are not the
Administrators group.
Click Remove.
Click OK.
Log out of the box and back in with the account that you just made an
administrator.
You should be all set.
Let me know if this works!
Best Regards,
~Will