This question already has an answer here: After update, get “error: file not found.” followed by “grub rescue> _” 5 answers last night i was trying to upgrade my ubuntu 12.04 to 12.10. every update was completed and finally when it asked for restart ,i restarted the system, then onwords it is not starting up showing message error:file not found. grub rescue> _ can any one plz help how to get rid of this problem. my system is dual os (windows 7 and ubuntu ) hp pavellion dv4 series