After I upgraded Grub and after my laptop restarts, I get a "File Not Found" error and then entered into Rescue mode. I tired to look for a list of files from my /boot partition and attempt to do insmod but is still end up with "File Not Found". What can I do to solve this problem? Do I need to restore the boot loader or reinstall Debian?
Grub Available only in Rescue Mode
Remind this at first that, your upgrade does not install until your reboot installation.
If you are continuing with a multiboot configuration, the boot menu that uses with Grub, might be different from the boot menu that pre upgrade modifies. In such a situation, you will need to point grub to the appropriate file for completing your upgrade upon reboot the PC/laptop. If this can't work properly, once pre upgrade has completed downloading and installing files, upon reboot no change will be disappear with this . The system will simply reboot as like it's older versions.
For a more perfect understanding and solution grab this all from the following site- http://fedoraproject.org/wiki/How_to_use_PreUpgrade
I think this all help you to get relief best. Thanks.