LinkThis is serious sam 3: BFE (not FFE). As you can see the most recent trainer marked as #1 is compatible with Windows 10. However, trainer #25 released over 5 years ago is NOT compatible with Windows 10. So, which one are you downloading?
Also, in regards to the other downloads you mentioned, our trainers for Serious Sam 1 are already FREE so you could have gotten them without a premium membership.
LinkSame thing with Serious Sam 2, all free.
LinkSame thing with Serious Sam: The Second Encounter, all free.
LinkOnly other title is Serious Sam HD which is clearly marked as RETIRED and no longer supported.
LinkIn regards to Homefront, again, the most recent trainer marked #1 is compatible with Windows 10 and the oldest trainer from 5 years ago is not.
For your reference I have taken a screenshot of the most recent SS3 and Homefront trainers running fine on my Windows 10 PC.
LinkNow, if there is anything more I can do for you, please ask, but all of this could have been avoided if you simply checked the compatibility and status of the trainers that you wanted before upgrading.