In my PC I had windows and Ubuntu 12.04 32 bit parallelly. I wanted to only replace Ubuntu 12.04 32 bit by Ubuntu 12.04 64 bit leaving windows untouched. I burnt the 12.04 64 bit ISO file which was available in our institute web repository (around 700 MB) in a CD and used the CD to install 12.04 64bit. Everything was alright and it also said that the installation was complete and asked me to reboot. When I rebooted the system I received the following:
error: file not found grub rescue>
I didn't know what to do further. I searched a bit in here with this error message, couldn't find anything favourably. Can someone help me out? I am bit shaky in computers. If you can explain it in layman's language, it would be of great help. Thank you.