Welcome back.
I'd recommend you take a look at Beacat's Nugget's Guide, on the Ubisoft forum:
http://forums.ubi.com/eve/forums/a/t...3/m/3181081438
As far as installing IL-2 under Win 7, the consensus seems to be that you shouldn't install it in the 'Program files' folder - create one for it instead, e.g. C:/Games/ or something similar. If you've already installed it in the default location, you can copy across to a new one without difficulty.
If you have 64 bit Win 7, this may be relevant too:
http://forums.ubi.com/eve/forums/a/t...5/m/2861000908