To pin facebook to my taskbar

First of all Check your device's date and Time if it is correct or not . if not, then change your device date and time and open facebook in new browser tap. This should work. However, if this will not work then follow this link below
HSTS and Pinning Certificate Errors and BPB quot Your connection is not...

If you can't log into Facebook and need to reset your password:

1. Go to the login page at www.facebook.com
2. In the top right, click Forgot your password?
3. Type the email, phone number, full name or username associated with your account, then click Search and follow the on-screen instructions

and you can also try the following link:
Forgot Password Can Log In Facebook

What probably happened is it asks for a pin emailed or texted to you since you are using a different machine/place to access FB, as in your computer or TV. Try logging in with your computer or smart phone and see if you can. And then try logging in with your TV and asks for a pin again.

Check the time setting. See whether it has synchronized recently with windows server, and displays the correct time now. Point the mouse ove the time display, at the lower right of the taskbar, right-click one it, and look over the window appear then. If necessary, adjust the Month, Date, Year and Zone. . Click apply > OK. Restart the system, and check.
Gopakumar Gopalan Google

Try any other Browser or re-install the browser you are using

Simplest solution is that change your facebook acount password then it will be fine.

on google chrome click the wrench icon go to tools the click the clear browsing data then exit then right click your network connection icon located on you taskbar then click repair then let it do its repairing process then try to log onto facebook again

ive put a pin and user name in i chose but it is saying error what is the problem?

Log out, then go to http://www.facebook.com/reset.php
Enter your e-mail address to be sent a new password, then log into facebook with the new password and change your password in Account Settings to your old password.

When you say "after u start the computer" you mean before you log in? The taskbar never shows up until you're logged in, so that's the way it's supposed to work.

If you've logged in and you still can't see the taskbar, it's possible that you've configured the taskbar to "auto-hide." To see if that's what's happening, move the mouse all the way to the bottom of the screen, and the taskbar should pop into view. Unless you've moved the taskbar to the top or side - check by moving the mouse all the way to each edge of the screen until you see the taskbar.

Once you see the taskbar, you can right-click either on the "Start" button or on the clock at the opposite end of the taskbar, and select "Properties" from the menu to turn off auto-hide (if you want to - some people like it once they're used to it). If you want to turn it off, pick the "Taskbar" tab on the Properties dialog, and uncheck the "auto-hide the taskbar" checkbox. Then click OK, and the taskbar should stay visible.

Hope this helps.