HELP! can not log in to admin panel after install win7

Yesterday I installed Windows 7, after that I can’t log in to the admin panel. I tried https://www.mywebsite.com/wp-admin/ and https://www.mywebsit.com/wp-login.php, both are page not found. I don’t have wordpress installed in my laptop right now, because I don’t know if I need to download and install a new wordpress to my laptop? How do I make changes to config? I have all the files in c-panel. I believe everything is online, does it to do anything with the physical computer i am using? Thanks thanks!!