Deleting ntuser files will NOT make your PC unbootable... Win 10 creates a temp account for you to log into
Firstly, if you don't know what it is, it's *not* suspicious. As you found out... Make it a rule to live by. Secondly, if you do decide to delete something without knowing what it is, back it up, first. (Of course--just shunt it to the recycle bin and let it sit there for awhile.) In the normal process of computing there are hundreds of things happening, programs running, etc., for each *one thing* the OS asks your permission to run. That is, in the normal course of things you will be completely unaware of hundreds of things running in your system for every one program you know about consciously. That is not "suspicious"--that is normal. Open up the task manager and check out the "Details" tab and you'll get the picture. Also...I've done this myself--if I see something I don't recognize and it bothers me I will Bing/Google it before taking any action whatsoever--and 99 times out of 100 I discover it's perfectly normal (But the 100th time I discovered I had developed a Bitcoin mining virus!) The great thing is that every time you do this you add to your general knowledge about your system. Good luck--as someone mentioned above--you have received a valuable lesson here! (Everybody who operates a computer has at one time sat just where you are sitting. So long as you learn the lesson there is no shame in it as we have all been there.)
just format C: /q and reinstall. What? 20 or 30 minutes and back in windows to delete the windows folder next.