Installing Windows8.1 after Linux Mint

I'm going to wipe the existing winXP partition and substitute it with Win8.1.
The Linux Mint install should be retained, therefore I need to run the installation of the SOs in the generally-not-suggested route: first linux than windows.

There shouldn't be any major issues, also because my PC is quite old and it shouldn'e be starting in EFI mode (aka "Secure boot"), but in the common BIOS mode (aka "legacy boot").

To check the booting mode:

The simplest way is to check for the presence of a /sys/firmware/efi directory. The mere existence of this directory indicates that the computer has booted in EFI mode

 or else:

dmesg | grep -i EFI
A BIOS-based computer will lack most or all of these lines, and certainly the EFI: mem## lines.

Still on EFI booot, check this link.
 
To repair grub:

• Boot-Repair
• is it available for my Linux Mint LMDE Mate 64bit install?
• Rescue dedicated distro, such as Rescatux, UBCD, PartedMagic, Hiren's boot CD, Trinity rescue disc...

To reinstall grub:
Boot  a live CD (mint 64bit in my case) and fire up a terminal.
Identify boot partition with

ls -l /dev/disk/by-label/

Reinstall grub with

sudo grub-install /dev/XXX

 
This should work.....