If OBS is crashing due to Elgato's drivers, follow these steps (carefully, in order!) to correct it.
1) Unplug your Elgato device (if USB)
2) Uninstall all Elgato software and drivers from Add/Remove Programs
3) Reboot your PC (Very important you do this before trying to install anything else)
4) Reinstall the Elgato software/drivers
5) Plug the Elgato card back in (if not already prompted to during the Elgato software installation)