Hi, kristbulu
The shane's advice is the only solution. No other fix. Because, numerous registry entries are created when one user account is created. I will advise you to create a new user with administration right, not just standard rights. Otherwise, you may not be able to edit some system files in the system.
After copying your old files from, your old files from c: user\username with some exception ntuser.dat, ntuserlogfiles as per micrsoft article on how to copy files from old user. Your problem will be solved with all the files intact. While copying files, pl check whether some unwanted programs exist, and you could delete the old user account after all the actions.