To access the built-in Home Administrator account you need to boot into Safe Mode:
After the power-on and BIOS POST or your Logo screen repeatedly tap the
F8 key or hold the
Ctrl key before Windows starts.
Among all your other accounts one will be Administrator. This account should be pure if you never accessed it before. From this account you can delete all others and create new ones although you will lose all the old data as well (IE and OE settings and Favorites and e-mail etc.).
While here I would rename the Administrator to something else and also put in a complex password such as
kH^%43ht&8Po* any 12 character mixture of cases; #'s and symbols. Just don't forget to write it down for yourself.
Then create a new working account for yourself with another complex password and delete all other accounts. If you want to attempt to transfer data you can try the following:
How to copy data from a corrupted user profile to a new profile
http://support.microsoft.com/default...b;en-us;811151
If there are only these two accounts and they are password protected then there is no other access.
On a simpler note just keep him away from your laptop.