unclean shutdown causes lucid stop booting

[Tapas Mishra]

Here is a situation I am having a laptop where
I have 2 installations of Ubuntu 10.04 and 9.04
I was working with 10.04 version.
After some time I switched it with command poweroff.
Now I am not able to boot to 10.04
How ever I am able to get to 9.04 and continue work.
Let me know what should I do to over come this situation on 10.04 64 bit.

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