Hi, I am in the process of updating my centos 6.3 to 6.4.
Now that they are developing Centos6.5, It is somewhat late to report this problem but I haven't been using my Linux as much since I got a new windows7 laptop.
Anyhow when I ran yum update I had to go through a massive list of updates(572).
I could see that updating from 6.3 to 6.4 is a giant leap.
Anyway, I think this is where the problem started.
When I used yum to update it, there was a instability somehow and the computer crashed during the process.
Well thanks to crash, now I am getting a massive list of duplicates every time I use yum.
I got to say, it is really frightening to see about 800 list of software just pop up during my yum install process. **BHAM**
Where do we go from here?
Any help would be appreciated, dudes.

Restore from backup and try again? (If you didn't then now you know why the documentation suggests making backups.) Or backup /home and install 6.4 cleanly? Or if you're sure you migrated to 6.4 successfully in all other aspects, manually remove each 6.3 package? Or rebuild the RPMDB database?

My Xserver is not starting giving cannot connect to xserver error.
Do you think I have failed to migrate to 6.4 in all aspects?

Thanks

Nevermind,
Installing the most recent NVIDIA driver (144.37) solved the problem!!
New driver said that it supports ABI 1.4 versions and I think that is what helped this problem.
Now my Xsystem is working fine.
Thanks for your advice.

Thanks for posting back your solution. Best check if you've upgraded OK though.