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I can't boot into a usable system anymore. What should I do?
I am using ubuntu 10.04-03 in virtual box.
All of a sudden today it doesn't boots up and shows (initramfs) prompt as shown below. Is there anyway I can fix it as I got really important data in it.
Try booting your VM with an ISO of Parted Magic and running a check and repair of the filesystem. It could be just a filesystem error.