In order to perform some tasks on your computer, your computer account must be an Administrator account so you have permission to make the those changes. You can easily give yourself administrator rights on your computer. To do this, you will need to know your exact login name. Your login name is the name that you use to log into Windows.
Right click on your My Computer icon (if it’s not on your desktop, it will be in your Start Menu). Click the “manage” option.
The Computer Management window will open. In the left hand navigation pane expand Local Users and Groups, click on “Groups” and double click “Administrators” in the right hand pane.
The Admin properties will now open so click the “Add” button.
In the text bottom enter login name and click the “OK” button.
Your name should now be added to the Members area of the Admin Properties window. Click the “OK” button, close the Windows Management window and you are now a member of the administrators group in Windows XP.
For this to take affect, you must log off and log back onto your computer (or you can just restart your computer, it’s up to you).