I have this working on my Windows 10 PC. In order to actually play it, I had to download a file called
xlive.dll and place that into my GTA IV folder in the '/steamapps' folder for Steam. Searching something along the lines of "GTA IV xlive" might get you that file.
I set some launch options for the game which make it run how I want it too.
-nomemrestrict -norestrictions-framelimit 0-noprecache-novblank -availablevidmem 2048.0 -windowed
You can try these - the last number can be edited to suit your needs (if you have more or less video memory available).
I'm not sure if the spacing matters. You can try appending spaces into there but I don't think it makes a difference.