I tried the 'keepres' trick but then the game didn't even start.
Well that's weird.
What size screen are you trying to run it on? Civ3 (usually) needs a minimum resolution of 1024*768, so if you're using a tablet or netbook with a smaller vertical pixel-count, but with "KeepRes=1", the game may fail to start (IIRC,
@Lanzelot figured out a workaround to that problem at some point).
If that's not the problem , then it
might be the Intro-movie which is preventing the game from running. So you could try (also) adding the line "PlayIntro=0" to the
conquests.ini, which will tell the game to skip straight to the menu-screen when you start it.
Other lines that I added:
"NoAIPatrol=0" makes the Barbs more unpredictable
"WindowsFileBox=1" gives you a normal Windows-type window when opening or saving games, rather than the simpler Civ3-default window.