How do I login as Root or Different User in Lion?


I bought this newer iMac from a friend who had the main user name set as "admin" and password as "password". I used this account to get all the software, fonts, etc. installed. When I changed the name and password and reset the computer it's like it saw me as a new user and everything I had done was reset with the exception of the fact that the software was all still in the Applications folder. I desperately need to get logged back in as the other user so I can get to the files I had dropped on the desktop and emails I had in Outlook. Thank you in advance for your help - I am completely new to Lion!
Open up (in the account you can get into) System Preferences->Accounts (User& Groups in 10.8.x) and their make a new User in the name you want and password. Then uncheck automatic login box. Sign in with that new User (make sure you make to have Administrative function) to test it works.

The log back in the original account(before you delete it from your new account) and the create a folder to save and documents, fonts and any other files you want in that folder. Than drag that folder to the folder /YourHardDrive/Users/Shared/ and drop that folder into there. Then log back into that new account you made and go to the same shared folder and move the file to same folders you got them from the other User account.

Lastly I will list the locations of fonts and personal data files.

1. User Fonts: /YourHardDrive/Users/YourUserName/Library/Fonts/
2. System Fonts: /YourHardDrive/Library/Fonts/
3. Pictures: /YourHardDrive/Users/YourUserName/Pictures/
4. Music: /YourHardDrive/Users/YourUserName/Music/

Any other files you need to move?

One more thing: Once you get all the files moved to their correct positions you can (from your new User account) you can delete the old account (as an Administrator account).

Also if you really want to use the Root User (a VERY BAD IDEA) look at the Apple document OS X: How to change user account name or home directory name. Just make sure you disable that Root account when you are done!
Thanks for the reply! Unfortunately I don't think this is what I'm looking for though. I am trying to access the original account on the computer that was being used before I somehow made a new one. I was not trying to make a new account - I only wanted to edit the name and password of the master account. After I did that and restarted the machine it acted like I was in a whole new account entirely and I could not see any of the files I had before, the desktop reverted back to a default, etc.
I was able to find the folders/files that were on the previous desktop by doing a search in the Finder window and dragging them to the new desktop. What I really need now is access to Outlook on the other account so I can get to important emails. Thanks again!
Keep in mind that "editing the name and password" of the existing account does NOT result in that same account with a new name. You only find that out when you restart, and the system creates a NEW account with the same name as the old one (before you "edited" it!),
And, there's nothing in that account, beyond what the system does in creating a default account.
Here's the quickest way BACK to your first account.
Edit the name of your current user folder (change the name to something unrelated). You'll probably notice that your current user is AGAIN named admin, and not the name that YOU changed.
Change the user account folder to the OLD name (admin, I think you said), and restart your Mac. You SHOULD then be back in your original account, with your old files and apps.
One possible problem, is that IIRC, the account name "Admin", is one that OS X considers a "special" or protected name. The system might not let you change the user folder to that name. It's a shame that your "friend" used THAT name for the first user.

Anyway, now you know that OS X will fight you every step of the way, unless you know the "rules" about the user accounts.
Best way to rename a user account, is to create a new user account (in System Preferences/Users & Groups pane) Log out, then log back in to that new user. Copy all your files to the new account. Delete the old account (only through the Users & Groups pane). I don't think you can delete an account named "admin" (remember the "protected" name?), unless you are logged in to the "root" user - which is a whole other subject. Or, you can choose to ignore the "admin" account, using it when you need a little help if needed for troubleshooting your system. Good to keep one account that you don't often use.