We do not officially support CotN version of EU2, for that you should go to SF support.
However I can offer you a few things to try.
1) Make sure you have set color depth to 16BIT.
2) Rename your AVI folder to AVI_back.
3) Try diferent resolutions.
4) Update your Sound drivers.
5) Run DXdiagnostic.
6) Set font size to "normal"
7) Disable any programs running in the background, Like Virus protection, or Instant messanger, things like that. Basically have nothing in your system tray, or minimized.
8) Reinstall and do not install any mods, see if it happens with the clean install and no patches.
However I can offer you a few things to try.
1) Make sure you have set color depth to 16BIT.
2) Rename your AVI folder to AVI_back.
3) Try diferent resolutions.
4) Update your Sound drivers.
5) Run DXdiagnostic.
6) Set font size to "normal"
7) Disable any programs running in the background, Like Virus protection, or Instant messanger, things like that. Basically have nothing in your system tray, or minimized.
8) Reinstall and do not install any mods, see if it happens with the clean install and no patches.