How to log on as an "Administrator" on windows xp .......?

If you set up Windows with only you as the user and no other user profiles then you are automatically the administrator. Just log in as normal and you will have administrator rights to view hidden files and make all the changes you need.

You probably are already the Administrator.Go to the control panel and check on the user accounts. Then choose :pick a task." Try "change an account". If you see your name, and under it, computer administrator, you are the administrator. If not, you may have to format your machine and start again. By the way, did you share the computer with someone else? If you did, you might have to have whomever he or she is, to transfer administrator to you.