Windows could not complete the installation. To install windows on this computer restart the installation

SHIFT-F10 to bring up command prompt.
cd c:\windows\system32\oobe
msoobe.exe
Make a generic account and password. 
Hit finish (if it requests a product key and you have one, enter it now.  if OEM/No key required, just finish). 
Set time/date. 
Finish.

Boot from grub2 rescue prompt

grub rescue> set prefix=(hd0,1)/boot/grub2
grub rescue> set root=(hd0,1)
grub rescue> insmod normal
grub rescue> normal
grub rescue> insmod linux
grub rescue> linux /boot/vmlinuz root=/dev/sda1
grub rescue> initrd /boot/initrd.img
grub rescue> boot