The checksum is displayed on the general startup screen (upper right corner). The correct checksum is LXES, which would imply all patches and CORE files are the ones they should be. If you have a different value your setup is incorrect (wrong patch, perhaps).
Chaplain reported serious CTD behaviour whilst having the correct checksum. But this worked for him:
In case it helps anyone else, I seem to have solved the CTD problem. I am running CORE in XP compatibility (SP2) with desktop composition and desktop scaling disabled. No more problems with CTD's.
We are looking into a CTD that is bugging us somewhere (presumedly) after Vichy is created. That one isn't always reproducible though, and usually reloading the last save suffices. But apart from that CORE should be pretty stable, certainly more stable than you're experiencing.