I ran a PC-Health to prepare for Windows 11 upgrade but it said my system does not meet Windows 11 minimum requirements.  I checked Dell computers tested for upgrade to Windows 11 and the m17 R4 is listed.  It said that 'Secure Boot' was not enabled.  I followed instructions to enable it by changing from Legacy Boot to UEFI, saved, rebooted, F2, and looked at the BOOT section again.  Secure Boot is grayed out and I cannot enable it.

Any ideas?