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Few months before when I was using Ubuntu 12.04 then I found some errors while starting my computer.
Due to this problem I had given my CPU to a shop to repair it I don't know what he has done to my CPU but I only know that finally I got my CPU with Ubuntu 13.04.
The technician was unable to make any partition and I also think that he had installed 13.04 over 12.04 and so now my computer is showing some error when I'm starting my computer the error is as follows:
error: attempt to read or write outside of the disk 'hd0'.
grub rescue > _
Before showing this error, few times my computer was working very slow.
So kindly someone tell me that is there any way by which I can start my computer.
Please also tell me that what things I have to keep in mind while using Ubuntu so that in future I find no difficulties(errors) while using Ubuntu.