What options did you use when installing Mint, I'm assuming Dual boot as my Mint PC boots straight into the OS as normal, but I did install it as the sole Operating System. If you went for a multi boot, what options other than Mint 18 are available when you press F8 ? You probably need to look at this bumph on Grub the boot order utility in order to set it to your requirements.
For an alternative to Comodo check out Sophos
As to using Windows recovery disks what type of PC is it ? Maybe somebody will have hands on experience in resetting one.