This is going to get a bit geeky, but it's a good answer.
Do your upgrade manually. That means, download the .iso file and install it if and when you are ready. Be back with instructions.
https://www.microsoft.com/en-us/software-download/windows10
That website explains the whole process pretty well. You can either download the .iso file and burn it on an empty DVD disc, or go with a USB stick. If you have questions, please ask. This way, you have 100% control over if and when you install Windows 10. eta3: You can also do the way Microsoft suggests (as in PoliticAverse's post), but to me personally, this way gives me more control. My quirk I guess.
eta: If you upgrade your machine that has a valid Windows 7, 8, or 8.1 license, you will pay nothing to upgrade within a year. If you try to install that .iso file on a blank hard drive on a machine that is not familiar to Microsoft at all, you will be forced to pay for Windows 10. My understanding is you can do a clean install on a machine known to Microsoft. Clean install means, you totally wipe the hard drive after saving all your important stuff, and then install Windows 10 fresh. Upgrades tend to bring problems, but I'll let you take the safest route if you wish. Even if you upgrade and run into a problem, you can then definitely wipe the hard drive and do a clean install.
eta2: A THIRD way to install (which I usually use) is to download the .iso file directly to the hard drive you wish to install on, back up all your stuff first of course, mount the .iso file by right click, find the setup.exe file within the folder it creates, click it, choose either the upgrade or clean install, and go from there.
= new reply since forum marked as read
