I've got a 80GB Intel X-25M running Win 7 professional - recently reformatted. When just this drive is connected everything is running well.
However, I also have a 1TB WD Caviar Green that was previously used for media storage. I didn't reformat this drive when I reformatted my SSD, and now when I reconnect the drive it frequently "hangs" at the windows 7 splash screen on startup. On a handful of occasions I've been able to get it to boot to the desktop. And when it does everything seems to work fine. When it hangs, If I unplug the WD, and reboot the system boots without issue.