It's not that complicated.
Open up your control panel, then open user accounts. Click on user accounts, then click on manager user accounts.
Now add an account - give it full administrator priviliges.
Now what you can do is use the Windows Easy Transfer utility and save all your information to an external USB drive/key (do you have one?).
Once done - re-login with your new account and just transfer the files back using the windows easy transfer utility. It may say computer to computer - but you can easily transfer the information to the same computer.
Using this shouldn't copy the file association.
Orrr...you can just live with it
it's not really that big of a deal - is it? Do you play around a lot with CFG files?