Ok
Lets do a basic thing here.
1. Was IL2 1946 running ok before you put the new Graphics card in ?
2. Is this a new Win 7 installation and new IL2 installation ?
3. If number "2" Has IL2 been patched correctly v4.07 > v4.08 > v4.09 > v.4.10
Just trying to get an idea what's going on
EDIT
Found this I assume its you, this has a better explanation what's going on ................
http://forums.ubi.com/eve/forums/a/t...5/m/3021083009
Assuming you have a clean IL2 1946 no mods
Download v 4.10 and reinstall you have probably got a corrupted DL