Hi charlotte...
If you are the main or sole user of the system:
Open control panel
Click on User Accounts
If you are already listed there, click on "change an account"
In the next window, click on your name.
A window will show with the question: What do you want to change about
your account?
Click on Change My Account Type
Tick Computer Administrator and then click "change account type".
Hope that helped.
Take Care...
Dee
