Windows 10 Upgrade

[xud]

Hi, some weeks ago my desktop auto upgraded from my ligitimate Windows 7 to 10.
Switched it on yesterday and it has come up with a completely different username at the log on screen. My old password doesn't work and neither does the admin.
What has caused this and what are my options to get back to either Windows 7 or back to where I was on 10.
Mike

[galeck1947]

If you have updated to Windows 10 in under a month then I would roll it back to Windows 7 then upgrade to Windows 10 at a later date . To roll it back to Windows 7 . Open the start menu select the settings app and go to Update and Security >Recovery and follow the prompts .

[Bazile]

galeck1947-why at a later date