I've installed Command & Conquer: Tiberian Sun, which I bought on Origin,
Bought? Hadn't EA released some older C&C Titles, among them Tiberian Sun+Firestorm as Freeware???
As of February 12, 2010, Electronic Arts licensed Tiberian Sun and its expansion pack Firestorm as freeware.
AFAIR those Downloads I played under Windows XP (not sure if I tried it under XP x64) - time to check 'em out under Win7 64bit.
Back to your Problem: You mean C&C installed via Origin and Dreamfall in what fashion? And which OS exactly?
Even if n-Games in different directories should all be named game.exe that wouldn't be any problem - first time I hear of such! Sounds like either a badly messed up Registry/Origin Install or some weird Windows 10 Microsoft User Convenience Magic!
Even if renaming the file is a workaround, knowing the true culprit would be a good thing, because it is something that either is easily fixable (registry edit/file path/environment variable) or should (IMHO/My 2ct) be fixed by those responsible (MS, EA or whatever third party app may be meddling here).
Edit: Tested the Tiberian Sun Download from my old Archives with XP x64 and Windows 7 X64... and at least starting 'em in Tiberian Sun or Firestorm Selection and Playing around a few minutes doesn't showed any faults... getting 'em to start required partition C and Program Files Folder [*1] (as testing on x64 I've chosen the (x86) folder and therefore edited the .lnk files in the EA Games folder to include that in target location and working directory)... Compat. Mode was set to XP SP3... Instead of using the .lnk "play tiberian*" to start the game, just executing the game.exe within the subfolder was also working fine... installing GoGs Dreamfall TLJ (64bit) in addition does not rendered C&C:TS unstartable....
(1): I am to lazy right now to investigate any further -> i am pretty sure that on my XP SP3 IBM T42+ Thinkpad (may it R.I.P.) i've played that TS Download from my Program Partition (D:) and not from the (OS) C-Partition... So that Program Path/ C Drive requirement could be circumvented without any workaround, but just editing of lnk/ini/etc files... or it just worked under older Win OS from anywhere (considering the needed changes in the *.lnk properties) and just NT~6+ OS are in dire need of the Program Files Path....
Edit 2: Ok, confirmed - just copied the EA Folder from the old Download on an USB Stick and started the game.exe from that drive within a XP-Mode VM (so it was Drive D) and it all was just fine.... So, with the proper edits in the OS settings it (the freeware version from EA) should also work fine at least up to Windows7/Server2008R2 (including 64bit) with the proper settings within OS and corresponding files... not much help to the OPs question, but i just was really curious about the "bought" statement for a formerly free title....
P.S.: If the bought includes working WAN-Multiplayer via Origin, then that would be another topic - my argument is only (LAN, I am not sure, option is there (untested)...) Single Player....