if this is a clean install of windows 7 microsoft did a few things. one they moved the path of there update server and drop a fre programs to make sure your windows 7 was good. if eather one was wrong windoww 7 would not update. another issue that hit any windows uses is a damaged windows update file. windows is not smart to toss it and then try again. turn off windows update service and then gogole on deleting windows update folder. after it deleted reboot and see if windows will update.