Format my Sony laptop

HELLO.
I HOPE ALL OF YOU ARE DOING WELL.
I am a new mumber here;
could please help in how to format my laptop.I did try and did all the steps but didnt work.I actually made another copy of my session or of the the administrator i already have ......I mean when i start my laptop they show me that black screen with 2 options to choose; WINDOS 7 and another WINDOWS 7 .When i choose one it start either with that old session or the new one.I know that i created one inside the other but i dont know why!!!!!!!!because i did all the steps that should done:
it s urgent could you please help me out with this i would be thankfull :
thank you again.
PS: my laptop is SONY and both the windows i try to format and the new are windows 7.