Windows 10: After updation i am not able to use my laptop

I just updated the windows 10 home. I reset the laptop so that the update will insta in my laptop. But after the installation of the update.. my laptop shows incorrect password everytime i boot it up .. even i doesn't set any pin in my laptop still its shows the. Same message.. i restart it so many times but still get the same message..

I checked some videos on YouTube regarding to this problem. They said use safe mode in networking.. i tried the same procedure but i am not able to log in even in the safe mode.. i safe mode i am getting the same message "password incorrect. Try again"

Can anyone help me in this case.. i need to repair this problem as soon as possible...


Thanks

:)

 

Best laptop under $800??

Well the last one I suggested seems to be the best for 650$

EDIT: to facilitate your search...

Laptop GFX benchmark list

Laptop CPU Benchmark list

 

HELP! My Laptop has gone into SLOW MOTION!

Should be able to get a "step-by-step here;

http://support.dell.com/?~ck=mn

 

Programs not working

In post 26 there were steps listed to fix the operating system corruption.
Are you able to follow them?
In post 29 was the suggested dism repair command.