I have a legit copy of Windows 7 64bit and Medieval II: Total War: Kingdoms. My Expansion runs perfectly fine with the 1.5 trainer. I often play modifications like Third Age: Total War and Stainless Steel w/ the Trainer activated.
Your game crashing after hitting the 'end turn' hourglass button sounds to me like a corrupted game file. If you are playing a modification, maybe the mod you are playing is corrupted. Same thing if you didn't actually buy the game, torrented games can in fact be improperly packed and henceforth not work properly. Either way, I suggest reinstalling your game via it's CD-Rom or Electronic Counterpart.
If you can't find your CD, Steam has the Medieval II: Total War pack on sale right now for $10.50. That includes both the First game and Kingdoms.
Have you checked that you have 1.05 version of the game. I had little similiar problem but I found out that I didn't have actually 1.05 installed. I had only 1.04 which comes when you install game. 1.05 must be downloaded and install even if you have gold pack. Only where you don't need to install it is in Steam version.
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