Please can someone help me on how to unlock my laptop. I just bought a new laptop but my friend used a different password for it now I can no longer open or have access to it anymore and my friend too can't remember the password that he used for it.

Your friend can't remember his own password? Is it a BIOS or Windows password?

Turn it off with the button. Start pressing f11. Go to disk recovery, after backing up data.

How do you expect him to back up the data?

Also f11 doesn't work with ALL machines, only certain ones, and you are assuming that it has a hidden recovery partition.

If you really bought it from a friend, merely call them up and ask them the other pass word,

If you are the legal owner of the laptop, take it to a shop where after checking the serial number for theft they will do this for you if your friend can not reemmber his old password