Doing a clean install?

Then your old OS will still be legal. Why not partition your hard drive and keep your old OS in case of problems?

When I had a shop build my Win 7 desktop, I paid a little extra to have them install my legal copy of XP on a small partition. It ran some old software that didn't do well on Win 7.

If it is an upgrade from a previous OS, it is a violation of the End Users License Agreement to keep both the new OS and the old OS installed and activated at the same time. Choose one or the other, but not both.

Because, aside form licensing, dual-booting brings along it's own set of problems and issues.

I don't get the fear of a new OS. If you do a little research ahead of time, there's only a very minuscule chance of something going wrong where your old OS is needed. If you are in the very small group that needs to maintain an old OS for software compatibility, you can just virtualize it.

In Vince's case, he didn't need to spend any extra money, as Windows 7 included XP Mode. Virtual Player and VirtualBox are both free alternatives, too. The only downside to this option is that a second license is needed for legality sake.

Right you are, Navy. But I'm not talking about an upgrade. I'm talking about a clean install of 10. If you make a clean install on another partition, your other OS will still be legal.

Right you are, Navy. But I'm not talking about an upgrade. I'm talking about a clean install of 10. If you make a clean install on another partition, your other OS will still be legal.

Only if the clean install of Windows 10 is made with it's own PURCHASEDproduct key and not the digital entitlement that came from the upgrade.

Valid point, Navy. You have to actually purchase a Windows 10 DVD with its own key to legally keep your old OS. Plus, it appears to be impossible to simply install Win 10 on an empty partition without providing them with a legal key number.

Plus, it appears to be impossible to simply install Win 10 on an empty partition without providing them with a legal key number.

That would be incorrect. You can do a clean install by clicking on "I don't have a product key" or "skip" or "do this later" when asked for a product key. If you install the same version and edition of Windows 10 that was previously activated on the computer with a digital entitlement, it will activate again by retrieving that digital entitlement from Microsoft activation servers.

Thanks, Navy. I hadn't known that.

A reputable computer shop that built my desktop told me that it is completely legal to simply install Win 10 off the internet on an empty partition. After reading your first post, I checked the MS site and saw that you are correct.

But if you can use a partition to keep a legal copy of an older OS, I think it's a good idea. I have a legal copy of XP on my rig, and it runs some old programs that 7 and 8 would not run. (Strangely, Win 10 can run most of those programs). I still have my legal copy of 8 on a third partition, although I rarely use it. And I installed 10 on top of a legal copy of 7 that I had stopped using.