The information you cut and posted from the bootinfoscript shows that you have an MBR system with Grub installed to the MBR of two drives (sda and sdb) while you have windows code in the MBR of sdc. What happens when you set sdc to first boot priority in the BIOS? The set root='hd0,msdos3' you posted from your machine confirms that it is MBR.

I'm not sure why you are geting an ntldr is missing error since ntldr has not been used on windows since xp. Vista and later versions of windows use BCD and the necessary boot file are: winload.exe which is on the system partition in C:\Windows\System32\Boot folder.
BCD is in the Boot folder of the boot partition or the system partition if you do not have a separate boot partition. bootmgr is also needed and is in the root of the system partition or the boot partition.

No. Detailed info on GPT at the link below. FreeBSD and most Linux systems can use GPT with MBR systems. Macs and windows can not.

https://en.wikipedia.org/wiki/GUID_Partition_Table

If you are still having problems, I think your next best step is to get boot repair, either by downloading it and burning it to a CD or running after insalling it on Mint. See the link below. Make sure you select the option to Create BootInfo Summary and just post a link to it here.

https://help.ubuntu.com/community/Boot-Repair

Jack, Hydrurga & Yancek,
Thanks for your help here - Boot repair disk worked & I've rebooted to GRUB choices several toimes to check.

In case it's of interest, the Boot info is here: https://paste.ubuntu.com/24204792/
My disks are in a right mess, I think, with old OS's but I'm not sure which ones to get rid of & which to keep - SDA was a new SSD with a W7 then LM17.2 install and the other disk still has the old W7 & LM 17.0 on it. I think. It worked & I moved on - I kept the old LM as a backup (glad I did as it's been very useful with my ongoing uninstalled QGIS problem)
Cheers
J

PS Jack, get boot repair disk just in case - it's good.

I'm glad it worked. Onwards and upwards!

If you have sda (256GB drive) set to first boot priority, you should be able to boot windows on that drive as well as Mint 17.2 which is also on that drive and Mint 17 Quiana which is on the sdc drive (74GB) as there are correct entries for all in the grub.cfg file of Mint 17.2 on sda3. There is also an entry for windows 7 on sdb1 (320GB drive so they should all boot.

Your grub.cfg for Mint 17 Mate only has entries for itself and the windows on sda1 so if you have the small (74GB) drive set to first boot priority, you will only be able to boot Mate and the windows on sda unless you run: sudo update-grub from Mate.

@mogmog, glad you did get it figured in the end without to much hassle. Iv kept a note of the repair disk just in case, thx.

Keep at it

Not sorted!
Just booted this morning - NTLDR is missing...
After running the boot repair disk, I rebooted several times & it worked, booting to the options menu.
Will try again with boot repair disk...

Back in 17.2 at present - this is the GRUB tool I found Rescatux:
http://www.supergrubdisk.org/wizard-...er-grub2-disk/

EDIT
Just re-run Boot Disk Repair & rebooted - now works. Will it stay fixed?

It should have worked with the SSD as first boot priority, at least from the info posted earlier. As long as you don't move drives, it should work. That grub.cfg shows all the correct entries.

Which selection are you making when you get the ntldr error? One of the windows entries, any menuentry? Your boot repair output usually shows the various boot files for Linux and/or windows and yours doesn't show ntldr but rather the correct bcd boot files for windows 7. Did this system originally have xp on it?