Fiction: Windows 7 and Windows 8 machines will upgrade directly to Windows 10
Win7 and Win8 machines won't quite upgrade directly to Win10. You need Windows 7 Service Pack 1, or Windows 8.1 Update 1, in order to perform the upgrade. If you don't have Windows 7 SP1, Microsoft has official instructions that'll get you there from Windows 7. If you're still using Windows 8, follow these official instructions to get to Windows 8.1 Update. Technically, there's a middle step on your way to Win10.
Fact: We have no idea what will happen when Microsoft releases a really bad patch for Windows 10
If there's an Achilles' heel in the grand Windows 10 scheme, it's forced updates for Windows 10 Home users and Pro users not attached to update servers. As long as Microsoft rolls out good-enough-quality patches -- as it's done for the past three months -- there's little to fear. But if a real stinker ever gets pushed out, heaven only knows how, and how well, Microsoft will handle it.
Fact: You'd have to be stone-cold crazy to install Windows 10 on a production machine on July 29
There isn't one, single killer app that you desperately need on July 29. Those in the know have mountains of questions, some of which won't be answered until we see how Win10 really works and what Microsoft does to support it. If you want to play with Windows 10 on a test machine, knock yourself out. I will, too. But only a certified masochist would entrust a working PC to Windows 10, until it's been pushed and shoved and taken round several blocks, multiple times.
You have until July 29, 2016, to take advantage of the free upgrade. There's no rush. Microsoft won't run out of bits.
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