For example, maybe you used a tool like Paragon Hard Disk Manager Suite to resize your OS partitions. Then you tried to reboot, and you got a GRUB error message followed by the GRUB rescue prompt.
There are several ways to reinitialize GRUB, and most of them involve live CDs and mounting partitions and all kinds of other tricks that will probably make you crazy unless you’re a command-line commando in linux.
Well, I don’t mind the command line, but I also have better things to do.
Fortunately, there is a MUCH easier way to save the day: Boot-Repair!