— run to find out the hd location.
df -hT

— as root
init 1
umount /dev/sda4 — change to each of your mapped entries above

fsck -NVr — for a trail run
fsck -Vr to actually fix

if you are presented with warning about unmount drive go to above and unmount.
Without specifying a partition to check all partitions in fstab are checked. Make sure they are all unmounted first. You are warned if a check on a mounted drive is going to be performed.

then either

shutdown -r now

init 6

Reinstall Grub after window install or other guest linux has taken over

I recently installed linux mint. It did not give me the option of installing grub or not and installed its own version / config into the mbr.

To get back to square one

Log into the Linux OS you want to have the grub mastered on and as root run grub-install /dev/sda (this might change depending upon the location of you MBR)

If you are reading this and stating; how can I do this if I can not log into my Linux OS; use a live disc, map / swap and as root run grub-install