gameon: For some reason the integrity check pops up twice every time. It doesn't seem to change with UAC on or off.
For me it always (IIRC) seems to go like this, at least on my two different Win7/64bit PCs:
If i simply (left) double-click the setup_<game_name>.exe file, it does the integrity check twice before starting the actual installation.
If I right-click on the setup_<game_name>.exe file and select "Run as administrator", the integrity check is performed only once before starting the actual installation.
Other than that, so far I haven't seen any difference between the two methods, but I guess it is more foolproof to select the second one, "Run as administrator".