Just fyi now ......
Modern laptops can have up to 6 (yes 6) partitions on them . It doesnt take much to screw up the bootloader
as the partitions are sometimes in weird orders (ie the Win partition may not be the expected 2nd partition)
Since the partitions are all in weird orders, the usual easy fixboot etc type commands wont work.
Blame the manufacturers for filling them up with crap instead of the clean installs that they should be .