/dev/sda1: Windows Partition (50GB)
/dev/sda5: Linux Root Partition (25GB)
/dev/sda6: Linux Home Partition (25GB)
/dev/sda7: Data Partition (220GB)

Executing:
grub-install /dev/sda
Error:
/boot/grub/stage1 could not be read correctly (something like this)

Executing:
grub
root (hd0,4)
Error:
filesystem type unknown, partition type 0xe