I think primarily the problem with this is that start up and shut down have slowed tremendously since I've first received this message. I have been googling this for months to try and correct this problem. Also receive a message about TPM. Any suggestions would greatly be appreciated. Thank you.
You have to go into your CMOS settings and disable the BIOS shadowing... though my guess there is something else wrong as this setting has probably been enabled since you got the computer. BIOS shadowing isn't necessarily a bad thing... but there really isn't any advantage to having it enabled on a modern computer. Back in the stone age of computers, there was a definite advantage, but not anymore.
How old is the computer? Have you checked the hard drive to see if there are any issues with it? Slow start up and shutdown is usually indicitive of a software / malware issue... but it could also be a problem with the hard drive. You might also want to check your motherboard's capacitors to see if they are in good shape.