how to set a default user for mac

hi guys,
Recently i tried to change the home folder name of my mac mini. i have gone through a website and followed some instructions to do that. finally i have ended up by creating a completely new user profile with a new home folder name.
after some time i have decide to turn back to my old user and deleted the recently created user.
This is where all my problems started. Now my deleted user folder is in my hardisk with the the follwing name - alpha(deleted). This folder is still being treated as my home folder even after logging in from a different user. I am unable to access even my keychain services through mac. Some softwares are asking me to reinstall on this user.... i ran into chaos with this.
Can some one help me to make my current user as default and renew my keychain access... Please help me as this is of high priority for me..
Thank you.

Did you follow the directions given by Apple on how to change the user name of your home folder? LINK

Try to recover your original home folder. Follow the instructions given by Apple. LINK

If none of that works, you'll have to reinstall OS X in order to set things straight. If you feel a need to do that, make sure you backup your data and application settings first.