It's important to note that, notwithstanding what Microsoft say publicly, if you upgrade from a validly-licensed W7 to W10, you are not charged. This may not last forever. Also, if you start the operation from within W7 you have the opportunity to upgrade while leaving programs and data unaffected; before anything is changed it'll tell you programs that aren't going to work after the upgrade. (You should still backup your data before upgrading - and you should be doing it as a matter of course anyway!) Download the W10 image, burn it to a DVD and get cracking. All-in-all it's around two hours to upgrade and eradicate your support fears.