Are you playing it on disc by any chance? I know that I couldn’t get it working due to “Games for Windows Live”. I had to purchase it a second time on Steam before it worked (since they removed GFWL from the Steam and GOG versions).
Tales of Maj’Eyal: An incredible rogue-like with 30+ classes and God knows how many achievements.
Cataclysm Dark Days Ahead: Apocalyptic rogue-like. Zombies, bandits, aliens and Lovecraft shit. Want to raid a dojo? Learn Judo from a book and proceed to race around town on a pair of rollerblades practicing on the undead? Feel free.
I recall a few games where I’ve had to limit the processor speed.
The weirdest one was an old adventure point and click. It was either “The 11th Hour” or “The 7th Guest”. It had a puzzle where you need to beat the CPU in a board game.
At the time it was released, it was possible. On a modern PC, not so much. The more powerful your processor, the more skilled the CPU was in the board game. Made it impossible.