Well Microsoft is freaking pushy.You could go to control panel - security/updating settings - > go to installed drivers/files and manually delete them.
Windows 10 keeps popping up all the time to say "hey, switch now."
Well I guess it didn't like that I kept pressing no, so when I awoke my PC it gave a 24 hour countdown to when it would auto update. Had to click through the menus and cancel that.
I had to do that yesterday when I went to update my win 8.1 gaming laptop.
Its amazing how they pushed the upgrade under three different Knowledge base files. I made two of them hidden because I remember the numbers but the third one (under a different number) got downloaded after my update last night. Deleted it manually before rebooting my laptop and did a check for updates for it to appear again and hid that.
So now I got three hidden "Security patches" that are meant for Windows 8.1 but are actually Windows 10 installers in disguise. Sneaky MS ;(!
No issues afterwards though.
I'll get Windows 10 for my new gaming desktop when I build it later this year.
