For those that might follow.... None of this involved data loss:
If this is a DELL machine.
In Windows - RUN - tpm.msc. If no TPM reported.
Tap F2 during boot to enter BIOS - look for TPM - if there - re-enable. Save and reboot.
If TPM is missing from BIOS - go to support.dell.com and enter machine service tag. Download BIOS update, run, follow promptsand allow to reboot machine.
On reboot - Tap F2 during boot to enter BIOS - look for TPM - if there - re-enable (or confirm it is enabled). Save and reboot.
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One other wrinkle - if the TPM doesn't reappear after a BIOS update.
Shut machine down, Remove power cord. Hold power button in for 60+ seconds to drain 'flea' power. Reconnect power
cord and reboot.
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Dell documentation is here:
https://www.dell.com/support/article/en-us/sln305777/tpm-option-is-missing-in-the-system-bios-setup-latitude-precision-or-xps?lang=en