Check in Control Panel>User Accounts to see if you're a Standard or an Administrator user. If Standard, click to change it to Admin.
That makes you an Administrator but the[/] Administrator is a higher level account and somethings can only be done using that account.
To do that, go to c:\windows\system32 and scroll down to the file cmd.exe then right click it. Choose RunAs Administrator.
A black Command form shows up and at the prompt, type
net user Adminstrator /active:yes
then hit the Enter key.
You should see a success message so close the form and restart the machine so you can log in to the new account that shows up.