ubuntu problem at login screen

[dokyounder]

I've been using ubuntu for 2 days, and it worked fine just few hours ago.

I turn the computer on, it takes me to the login screen, and I type the password then click login. Then it seems it's taking me to the main screen but the screen goes black and takes me back to the login screen again. I type the password again and again, but it's still taking me to the same spot. It's like I'm on a time-machine.

When it was working, I did make some changes.
First, I installed Dropbox, then rebooted. so I think there's no problem with that.
Then, I made some changes on the keyboard layout using this method (http://ubuntuforums.org/showthread.php?t=30981).
I think that's the problem, but I don't know how to restore it nor fix the problem.

any suggestions/comments/help are greatly appriciated. Thanks.

oh yes and I'm using ubuntu 10.04 netbook edition.

[varunendra]

There seem two possible reasons:


Your default keyboard layout might have been changed, thus typing different characters when you enter your password. To confirm this, you may try using 'On-Screen-Keyboard' at login screen (as told here (http://www.clickonf5.org/linux/keyboard-problem-ubuntu-1004-login-vmware/7163))
Some error in any of the essential applications or system modules. In this case, try booting in 'Recovery Mode' (press & hold 'Shift' key while booting) and selecting 'dpkg' there.

Also, while in 'Recovery Mode', can you log in as root (last in the Recovery Menu)?

Any further attempts would depend upon the results you get while trying these.