Windows Upgrade Help and more

This. If it was pre-installed, you might need to contact your PC manufacturer's support next.

+1 Did you also check if your BIOS is in UEFI mode and not Legacy?

Yeah, that's a common snag. You might also want to double-check if TPM is actually enabled in your BIOS, as it's sometimes off by default.

Agreed, they haven't added it yet. A quick workaround is enabling high contrast theme #1, which gives a much darker interface.