BIOS - LENOVO 5CKT54AUS, 9/7/2009
If this is a UEFI bios and it is that old.
They were still trying to get all the bugs out of UEFI and still working on exactly what it would or would not do.
There really was no set way for it to work, what it would look for, how it would react, etc....
A lot of it was up to the computer manufactures and how they wanted their UEFI to work.
The last few years everyone has settled on what UEFI would do and how it would work.
I wonder if that warning is just telling you that something other than Windows is trying to be used.
Puppy Linux is not providing the expected signature that Windows will provide.
As they say.
If it is not broken!
Do not try to fix it.
funny none of the UEFI computers I have give that message.
But they are using much newer versions of UEFI.
All of mine are personal computers or ones I built from a bunch of after market parts.
The ThinkCentre is a line of business-oriented desktop computers
they probably have UEFI access restrictions set tighter than a personal computer will have.