Yes, it is a 'free upgrade' BUT don't use the option 'upgrade windows' in the install menu!!
this will scan all your software and get it saved... OK if you have a day to spare, and a few retries... :/
If your win7 PC has the registration code on it (that DOES NOT have the OEM in the numbers!)
then you can use this for win 10
make sure all your software is available on CD or USB so you can do a fresh install later...