I Known My Password But It's Not Opening So, What I Do To Access My Account?

I am from Dell Social Media and Community.

Try logging in from safe mode from advance boot options, if still the same issue then follow the steps below.

Be sure and enter the login and password exactly, making certain to enter upper and lower case letters accurately.
Be aware of whether your caps lock is on (because originally some users put the cap's lock key on, and then do not realize they leave it on while putting in their information).
Note any numbers and letters that may be transposed, such as zero and the letter O, or the number one and the letter l.

If I were you and followed all the steps above and still not able to log in, it would either be that the password I am entering is the wrong one or someone else has changed the password and I would just reinstall the operating system. (if you have any important data, reinstall the operating system without formatting the hard drive so that you can back up the data once you are able to log in (Dirty install) then go through the reinstalling process by formatting the hard drive (Clean install))

Let me know if you need any further assistance, I will be happy to help.

Dell-Niranjan