I would say You actually can. But i guess this option will use Windows a little bit too.

Create a liveUSB with Ubuntu, in the moment, the actual version is 16.04.01, I don't think it really matters.
With this, you will be able to run Ubuntu on your computer.

Boot your device using your LiveUSB and open the 'try' Ubuntu version.

In the file things, get to : /'your os drive name'/Windows/System32/. If you can't find the drive, look for the drive that has the Windows file in it.

Find sethc.exe, name it sethc2.exe

find cmd.exe. Make a backup copy (I have to say i have installed the whole ubuntu thing, i was kind of deseperate .. hahaha)

Rename cmd.exe as sethc.exe. Good to go, let's restart the engine!

So now when you will open Windows, when you get to the log in page, press Shift multiple times, and the command prompt should appear.

Then, the fun part :

Create a new windows user acount from that command prompt : net user [Name] [password] /ADD

for example : net user Gege 123 /ADD

If you want to go without any password : net user Gege "" /ADD

and then if you want to make it 'administrator' here are the magic words :

net localgroup administrators [Name] /ADD

For me it would be : net localgroup administrators Gege /ADD

I hope this can help.