No Default Windows Password
Unfortunately, there is no real default Windows password. There are, however, ways to accomplish the things you wanted to do with a default password without actually having one. For example, there are ways to find your administrator password or any password you might not know, which you can then use in place of that fabled default Windows password.
Did You Forget Your Password?
There isn’t a magical password you can get that gives you access to an account that you’ve lost the password to. There are, however, several ways to find a lost Windows password.
Do You Need Admin Access?
Certain things you do on your computer require an admin to provide their credentials. This is because when the admin user was initially set up, they were given rights that regular, standard users don’t have. This includes installing programs, making system-wide changes, and accessing sensitive parts of the file system. If you have access to another account on the computer, but you’re unable to reset your forgotten password, you could just make a new user account and forget about the original (your files, of course, will be locked away in that inaccessible account, though). This is considered a destructive method because it will start you over from scratch, removing not only your forgotten password but also all of your programs, pictures, documents, videos, bookmarks, etc. Everything is removed, and the whole operating system begins again as completely fresh software. If Windows is asking for an administrator password, chances are there’s a user on the computer that can provide it. For example, if NormalUser1 needs an admin password to install a program because it’s not an admin, the administrator user AdminUser1 can put in their password to allow the install. However, unless the account was set up for a child, most user accounts were initially given administrator rights. In that case, the user can just accept the prompt for an admin and continue on without having to provide a new password.