getting rid of former user

You didn't mention which OS, but assuming you have Windows XP or Vista:

- create a new user with admin rights

- log in with this user (account)

- delete the old user account (and therefor all documents and settings related to the old user account)

yeah running XP. I've done all that , a while ago. I'm listed as the administrator and there's no other users on the computer. Even guest users are disabled. Do you know anything else I could do? Thanks for your help.

Windows 2000/2003/XP/Vista

Run the Registry Editor (REGEDIT.EXE).
Open HKEY_LOCAL_MACHINE\ SOFTWARE\ Microsoft\ Windows NT\ CurrentVersion.
To change the values of the RegisteredOrganization, RegisteredOwner, or ProductId, simply double-click on them.

Note: This will only change the registered user information for Windows, not for the applications on your system.

http://office.microsoft.com/en-us/outlook/HA011110031033.aspx

E-mail account  This is the account that you add to your Outlook profile by using the user name and password information given by your Internet service provider (ISP) (ISP: A business that provides access to the Internet for such things as electronic mail, chat rooms, or use of the World Wide Web. Some ISPs are multinational, offering access in many locations, while others are limited to a specific region.) or your Microsoft Exchange Server administrator.

Outlook profile  Your profile contains your e-mail account information, contacts, calendar, personal folders, and settings. You can have multiple Internet e-mail accounts in a single Outlook profile. You can have only one Exchange Server e-mail account per profile. Typically, you use only one profile, but it is possible to set up multiple profiles in Outlook.

Personal Folders file  This Outlook data file has a .pst (Personal Folders file (.pst): Data file that stores your messages and other items on your computer. You can assign a .pst file to be the default delivery location for e-mail messages. You can use a .pst to organize and back up items for safekeeping.) file extension and stores your e-mail, contacts, calendar, and other Outlook data.

Windows user account  This Microsoft Windows® operating system account allows users to have their own individual desktop, Windows settings, Microsoft Internet Explorer Favorites, History, and My Documents folder. Each user account can be protected by a password known as a Windows logon password.