Okay but, when you "run as Administrator" with notepad what happens? Does it prompt you with UAC for a "yes" or "no"? Does it require a username and password?
The other thing you can do is open control panel and go into User Accounts and select "Manage another user" or something like that and you should see all the user accounts on the PC and their permission level. Which one says administrator and is that the account your logging into? If not that you might want to figure out how to log into that account or back up data and wipe and reload with an account structure that makes sense.