Some of you may have managed to avoid upgrading from Windows 7 or 8.x but still have some interest in what Windows 10 is really like. Or perhaps like me you want to try the very latest test builds of Windows 10 to see what's coming up in the next release but don't want to dedicate a complete computer system to it and don't want to risk messing up your current stable Windows 10 installation.
For awhile when Win10 first came out I was on what's called the Fast Ring for test builds. These are the people who get the earliest, and sometimes flakiest, test versions. Once the second official release (build 1511) came out I was about to get rid of my test machine and I didn't want either of my other Windows computers on the test builds. But I'm still curious to see what's coming and have a chance to play with it from time to time.
More than just seeing what's available in the newest test builds, I also want to see some of the new versions of the apps. Microsoft is doing some interesting things with them and some of them will only run in newer builds which have the necessary support for them built in.
If you're interested, here's a way you can do it safely and for free. http://www.cnet.com/how-to/how-to-install-windows-10-technical-preview-as-a-virtual-machine/
It consists of installing Oracle's free VirtualBox virtual machine so you can run other operating systems on your computer without having to do complicated stuff like multi-booting, etc. VirtualBox runs on your PC just like any other app but it serves as a "host" that creates a completely isolated "sandbox" for the guest operating system to run in.
VirtualBox takes 153MB in the Program Files folder on the system drive .. not a lot of space.
However, a virtual machine running another operating system requires its own virtual hard drive. That's just space you allocate on any hard drive on your system. The virtual drive will look just like any other file except that the guest operating system running in VirtualBox will see and treat it like its own hard drive. With VirtualBox you can assign the virtual drive on any drive you want so it won't clutter up your system drive.
Of course if the drive you put the virtual disk on is a slower drive, as it is on my system, it will affect the performance of the guest operating system. But we just want to play around to see the functionality anyway so it's probably not a really big deal.
The article linked above is pretty good. Read it all the way through a couple of times to make sure you're familiar with what it's telling you to do. If you don't read the whole thing at least once you risk missing an important point or two (don't ask!).
The only thing I would add is that the link to get the Windows 10 ISO image file really isn't. That is, there's not a Windows 10 ISO file to download so don't waste your time looking.
When you get to that page you'll see a button to download the Media Creation Tool. That's what you need. Download it and run it. When you get to the bit where it wants to know if you want to upgrade "this" computer or create an image to install on another computer, select the option to create an image for another computer. Then select the option to create an ISO file somewhere on your computer (you can tell it where).
The Media Creation Tool will download the Windows 10 installation files and create an ISO file from them. (It's basically an image of the Windows 10 installation DVD.) This is the ISO file that will be used a little farther along in the article to install Windows 10 in VirtualBox.
Aside from that, you can follow the article as it's written. If you have any questions just ask here and I'll see if I can help. I've installed VirtualBox and have a virtual machine with Windows 10 installed and updated. Now I'm just waiting for the latest test build update to show up. UPDATE:
Well, that didn't work out as well as I figured. Before you waste any time on the stuff above, read the rest of the thread below. Or, for the TL;DR version (too long; didn't read) jump straight to this post: http://www.laptopgpsworld.com/5625-play-windows-10-without-upgrading#post49694