I tried to install HWinfo and got a message about that update. Can't install program otherwise.
Assuming you really don’t have KB2763674, that shoots down a perfectly good theory. The correct place to “search” is called “Installed Updates.” Windows Update was definitely still working when you reinstalled Vista in April 2019, but it might be that you never set Windows Update to give you Recommended updates in the same way as Important updates (in which case you might not have any Platform Update components either). No, KB2763674 was not superseded by another update.I did a search for the 276 update in my Windows History and didn't find it. I also did a visual check and didn't find it. I don't have any hidden updates. Perhaps that 276 update was superceded by another.
I did a search for the 276 update in my Windows History and didn't find it....
as far as I know this only happens on 64-bit Win 7 SP1 computers that have not been patched to end-of-support (14-Jan-2020) and do not have KB4474419 installed to add SHA-2 code-signing support.