Lost Password, Keyboard wont work

If you can log into the router you should be able to simply reset the guest PSK to whatever you like. If you have a computer that can successfully connect to the guest network you can open an elevated command prompt on it and type netsh wlan export profile name="ProfileName" folder="C:\" key=clear Replace ProfileName with the SSID for the network.

Go here for more info.
Offline Windows Password Registry Editor

have you typed in the correct password?

Either you made a mistake entering username and password or you have no right to access the computer. Try entering guest and no password.

Either you made a mistake entering username and password or you have no right to access the computer. Try entering guest and no password.

This isn't a password login problem - the User Profile Service service failed the logon because it's corrupted. Try to login in Safe Mode and access your account from there . If you can then retrieve all your files while you still can and prepare yourself for a reinstall.
If you can't then you will have to use a Linux Live-Cd like
http://www.pclinuxos.com/?page_id=10
to recover your files before performing a full reinstall.

Do a system restore to a time before when the keyboard was working. To do a system restore, go to Start >> All Programs >> Accessories >> System Tools >> System Restore.
Good luck!

It seems that the Guest account profile is corrupted because of which you are unable to log in as like in previously.

In the Profile Login page, hold the Ctrl and Alt keys and press the Del key twice.

This will give you a window where you need to enter the User name and Password.

Enter the User name as administrator and leave the password column blank if you have not set any Password to the administrator account or enter the Administrator password if you have set any.

Now once you are loged into the Administrator account, create a new User from the Control Panel > User Accounts.

Set the required limitatios to the account like limited account or administrator account and log off from the administrator account.

Now, you should have the newly created user account available in the login page. Select it and you should be able to login.

Sounds like the F key is stuck. If you can get the keytop off, you may be able to fix the problem. If not, you may need a replacement keyboard.
Hope this helps!
R-

Replace the keyboard as it seems the F key is probably jammed.