Posted 18 August 2009 - 05:40 PM
You could try this, it may work as long as there isn't a password on the default/hidden administrator account.
You need to logoff and get back to the screen where you pick which account to login to. To do this with only one account on the machine, just click Start and then go to Logoff. When your on the screen where it wants you to select an account to login, press Ctrl - Alt - Delete twice. It should change the screen to the Windows Network login screen. As the Username, type in Administrator and then try to login. Hopefully it will let you login as long as there hasn't been a password set on this account, if you know the password then enter it in.
Once logged in here you should be able to change your own account back to an Administrator account.
Hopefully that should work.