I changed my username like in this guide: How To Change User Account Name In Windows 8 (Yeah I know it's for Windows 8, my mistake:eek:)
Pressed Windows+R, typed netplwiz, changed my username, and...

I changed my username on Windows 10, and after a while I logged out. Then when I try to log back, it asks for password, but my old password doesnt work. I also tried putting blank password (not...