I’m using Win7 Ultimate and SGP runs flawless (with legacy SBIG ST2000 and ST10 cameras) with 32 bit SGP versions 3 and the latest version up to 4.0.0.643. As of today, I tried to run 4.0.0.651 and SGP doesn’t fully startup. So, it may be a limitation with the latest V4 version and Win 7. Here is a link to a recent discussion for this very same topic:
Mike