I wonder if the Ultimate upgrade was a bought OEM install as after either February this year or last year, MS stopped selling Win 7 anything and OEM installs could be bought off the Internet as an alternative.
While they will work, once an OEM version has been installed then it cannot be transferred to any other machine, unlike a retail version.
If you downloaded Speccy, under Operating System just above where it gives the product key, it will give the date of its install.
You should be okay to use that key for a repair install but it won't work for a clean install as you would need a retail key for the disks I've sent you, although you may be able to do a clean install with your disk - but that would have to be a try it and see.