I'm using full Windows 7 with nvidia GeForce 8700 GT, 4GB Ram, Intel Core 2 Duo T9300 2.50GHz. I'm also having this odd issue. I tried setting the compatibility mode for several versions, but it runs okay (except for the multi-group lag) on 7. Also, setting the 3D graphics didn't seem to help. I have been trying skirmishes, just to troubleshoot the issue, but i'll try campaign to see if it works there. Thanks and good luck!