It's not clear what you mean by a "duplicate account". Do you want to make an account with the same username? Do you want to make a new account, then restore your files to it?
It sounds like what you need to do in this situation is create a new user account, then transfer over your documents and settings. Since your user profile itself may be corrupted, you won't want to transfer that, but you can copy over most of your application data.
First, create a new account. Name it whatever you want, it just can't be named the same thing as any existing account. You can rename it later. Then, log off of all accounts except for the administrator account. From the administrator account, copy everything from
%systemdrive%\users\new_username except for
NTUSER.DAT.log and any other files like that. You may need to change your explorer settings to let you view hidden files and folders.
Once you have copied everything over, which may take a long time if you have a lot of files, log onto the new user account, and check to see if things are working. Some settings will not have been copied over, but your bookmarks, browser addons, files, etc. should still be intact. Once you are satisfied that what you need is there, you should delete the old profile so it doesn't take up space, and then delete the old user account.