As for all the conspiracy crap people keep posting - TL;DNR

I use NVidia almost exclusively. No driver problems whatsoever. Hmmmm.

So I can test skins on 7, and for a few other reasons. And I still like 8.1. Mainly just wanted to do it because I can....lol.

I used a great CoolerMaster case I bought for 20 bucks, used, of course, a mobo I had around, and a quad core APU.

Just a play rig, something to experiment on. I just wanted to climb the mountain "because it is there".

Win10 compatibility issues for hardware over two years old or so is still a very real problem. Anything issued on Win8 is likely AOK. Anything that started on Win7, let alone XP or Vista back in the day, has a lot of potential issues based on mfr support and, barring any of that, Microsoft's debugged and compatible replacement drivers (no, that's not a joke about mutual exclusivity - or maybe it is). Most PC mfrs are recommending their users do NOT upgrade - at least yet.

For now, anyone who started on an older OS, I would suggest trying a dual boot with another partition or HD/SSD to do testing, etc.

Just my $.02!

if you did it yesterday, couldn't you have just done a clean intall directly using win7/8 key with the latest win10 from this month?

you don't need multiple licenses for multiboots?

One of my PCs was running Win7-64. I purchased a Win8 Upgrade and decided to dual-boot and installed it to do so. I have relatives that are running Win 8.x and, as many here may be familiar, I have to de-facto support their computers, etc. since I'm the one with more experience. Anyway, when the free Win10 upgrade nagging began I decided to upgrade my Win8 partition to Win10. Currently I'm running a dual boot of Win7-64 and Win10-64 on that machine. I honestly don't know if that's legal or not. While questionable, I've seen nothing to say it isn't and I've spent some time looking.

What's interesting is that when I boot to the Win7-64 partition I still get the Win10 Upgrade nagging. My intent is to slowly migrate things to Win10 with some testing. Once all's working well I'll wipe the Win7 partition and have Win10 as the only OS on the PC, expanding it's partition.

From my current "moral" perspective, I don't think I have issues with dual-boot, especially since I don't intend to keep my old versions of Windows in the long term. Were I to use the Win10 upgrade advertised on my Win7 partition and end up with two Win10 partitions I would consider that a problem. Were I to start creating Win10 VMs on that machine I would definitely say I should have a new license for each.

Hope that rambling made sense!

And for anyone looking to dual-boot I just found this: http://www.howtogeek.com/197647/how-to-dual-boot-windows-10-with-windows-7-or-8/

Peronsally, I just downloaded the upgrade and told it to install on an open partition I had previously created. No issues.

Thinking...thinking...decisions...decisions.

You can't clean install (for free) until you have upgraded THAT machine. Once upgrade has been done on a machine, you can roll back and dual boot a clean install of 10, or wipe drive and clean install 10.  You CANNOT use a Windows 7 key, or a Windows 8 key to clean install Windows 10. It doesn't work that way. Not even AFTER upgrading.

After a Win10 upgrade, you may cleam install Win10, for free, on the same rig, and choose SKIP both times you are asked to enter a key. Once installed, Windows 10 will activate. (Must be on the same rig you previously upgraded.)

Yes, you need multiple licenses to multi boot.

One common misconception is that once you upgrade a 7 or 8 rig to 10, your 7 or 8 key is no longer valid. This is incorrect. Windows10 does not change or use your 7 or 8 key, it simply replaces it.

You can still use your 7 or 8 key after upgrading to 10.

Why would that be illegal?

It has been my experience, Ross, that in a triple or dual boot involving Windows7, 7 must be installed first. Otherwise you have to use a program to rebuild the MBR, in order to successfully boot the multiple OSes.

I use EasyBCD.

Quote:

EasyBCD is a powerful bootloader-modification tool that has a wide-range of applications and usages. It can perform a variety of tasks ranging in complexity and application from the most basic to advanced and highly-customizable features.

Please use EasyBCD with care, it’s a powerful tool that you can either make your life a lot easier or make it rather miserable by letting you shoot yourself in the foot.

EasyBCD is free for personal use at home.

http://neosmart.net/wiki/easybcd/  

You also need to be sure not to install 10 as an EFI OS, Windows7 does not support EFI and won't boot if the newer OS is installed in EFI mode.

Well, MS has changed the rules on me. What I said above in reply 24 WAS true.

But I just got upgraded to the latest release of Win10, and found this out.

Note

• Starting with the November Update, Windows 10 (Version 1511) can be activated using some Windows 7, Windows 8, and Windows 8.1 product keys. For more info, see the section Activating Windows 10 (Version 1511 or higher) using a Windows 7, Windows 8, or Windows 8.1 product key in this topic.

Link to article:

http://windows.microsoft.com/en-us/windows-10/activation-in-windows-10 

the november update (threshold 2) allows people to clean install (w/o upgrading 1st) with a win 7/8 key. or at least that's the theory... hence my comment

(hey.. could have sworn i didn't see your reply there )

ps... supposedly win10 newcomers (that is.. those who upgraded before threshold 2 came out)  won't get threshold 2 until 30 days (or was it 31?) after their upgrade (as it'll wipe their restore to win 7->8 thingy)... and getting threshold 2 will reset certain settings, maybe even revert some drivers to default ms ones.....

http://www.ghacks.net/2015/11/14/make-sure-to-check-default-apps-and-settings-after-the-recent-windows-10-update/

i'll have to go through a clean install soon.... fingers crossed.

I have Win 8.1 and I book marked the link from how-to-geek about dual booting with Win 10 and 8.1. It seems pretty straight forward but my concern is will Win 10 interfere or break anything on 8.1 even though its on a separate partition. Considering all the nonsense with the new OS I've come not to trust MS at all. Another concern are the drivers. All of mine have been updated to the newest versions from the mfr's website. They're all pretty much generic, no fancy nVidia or any of that stuff. If Win 10 imports its own its could screw things up royally. Good thing I got plenty of backups, redundancy is a good thing. 

Dual, Triple boot, nah. You guys have recognized that Hyper-V ist built in since 8 ?

I have a new, larger, SSD on the way. The old 128Gb SSD just wasn't big enough, I had to store a lot of stuff on another drive.

Once I've got the boot media on a USB I'll be clean installing W10 to the new drive