i have been using ubuntu 9.10 karmic koala since past one and half year.Day before yesterday it was working fine ,but when i started it again in evening it was not able to log in my account.i have lots of very important data on mu hard disk and i cannot afford to loose it at any cost,its so valuable for me.its a kind request to all the volunteers if they can help me rectify this problem as soon as possible.i am able to use the computer by booting from the ubuntu cd and using net.plz help me....