problem after increasing disk space in wubi, getting stuck in login page

Hi,
I have a very complicated problem I hope someone can help me.

I kept taking a warning from Ubuntu that the remaining space is less than a Gb. so I looked some forum to learn how I can increase the space of Wubi.
and find this http://superuser.com/questions/12599...tu-via-windows which says I need to do following

Download wubi-add-virtual-disk, open a terminal and run:
sudo sh wubi-add-virtual-disk /home 15000
Where the first argument is the directory to move to a new dedicated disk, and the second argument is the size in MB.

I did exactly the same and when I reboot, I entered my password, it did not work. A black page appeared whenever I entered my password and then I get redirected to the login page. At this time I was able to log as guest.
I look for some solution for this problem. I tried following.

press cntrl+Alt+F3, log in , then enter ls -lah (did not work)
enter ls -ld/tmp (did not work)
enter chmod a+wt/tmp (did not work)
enter chown username:username .Xauthority (did not work)
and finally i did
enter sudo apt-get update
enter sudo apt-get install nvidia-current

After this point everything get worse. Now I can't even log in as guest. basically ubuntu does not seem accessable at all.
I was wondering if some has some idea . I really appreciate that. I hate reinstalling Ubuntu as I have tons of stuff on it.

Thanks