Ok, new conundrum. The game in question is SimCity Classic, the Windows 95 edition. I got it off the internet and installed it on my Pentium III Windows 98 SE machine. The game runs perfectly fine... up to a point.

I'll start a new city and build and build and build. Apparently, I've figured out how to not suck at city building, because I don't have to cheat to get $100,000+ in my pocket, 50,000+ people (Capital), etc. But at some point during building, the game will simply crash the next time I select an item on my build menu (say I click on Industrial so I can lay down new blocks). Clicking the IGNORE button does nothing. Clicking CLOSE shuts the program off. This happens regardless of how long I've been playing. I've saved cities one block at a time. Once the city gets to a certain size, it simply crashes the program. I can load the city, click on a zone and watch it crash almost immediately - even after a reboot.

I'm in the process of loading up the error so I can copy the text here.

Ok, I just spent nearly an hour with my city and it never once crashed. Of COURSE it would work properly as soon as I posted this thread. Now it's a Metropolis with over 215,000 people and it takes up all available land mass.