I’ve automatically signed up for it~ how can I stop it now?
I don't know. If you have a recent full image backup from before you signed up for it, you might try restoring your entire machine from that. But I don't honestly know if that would do it. It's what I would try if it was me.
You may have just asked the $64,000 question.
You don’t have to install Win 10 when it’s available. You have a year and they claim that registering now doesn’t commit you to the upgrade.
You should have received a confirmation email from MS stating,
You’ve just reserved your free upgrade using the “Get Windows 10” app. You can also use the app to confirm the reservation, check to see if your device is compatible with Windows 10, and un-reserve if you wish to cancel your reservation prior to your Windows 10 upgrade.
As I recall the instructions for unreserving were in the instructions for how to reserve. I realize that may not be much help, but now you know there is a way to do it. Try googling “unreserve windows 10.”
No need to stop it. It will download to your computer, but it does not install automatically. You install it when you're ready. I suppose at that point you can delete cancel the upgrade if you wish.
You have a whole year after it is released to install it for free. If you don't like what you hear by then, you haven't lost anything but a few gigabytes on your hard drive.
If I change my mind, can I cancel my reservation?
Yes, you can cancel your reservation at any time prior to installing Windows 10. Here’s how:
•Right click on the Get Windows 10 App or Windows icon located in right end of the taskbar.
•Select “Check your upgrade status”
•Select “Cancel reservation”