For future reference for others with the same problem, I had the same problem described here. Mine is a Sony VAIO laptop model VGN-FW560F, running Windws 7 Home Premium 64 bit. "linleHP"'s response solved the problem for me as well. My laptop was working fine until I upgraded the hard disk from a WD Black 500GB drive to a WD Black 750GB drive. (I had previously upgraded from 320GB to 500GB with no issues.) Once I upgraded to 750GB I had issues begin to arise, culminating in an inability to boot on Friday night. I used the Windows 7 repair disk to get it to boot again, swapped in a new drive (same WD Black 750GB) in case that was an issue, but still could not run Windows update. What fixed the problem was downloading & installing the new Intel IRST drivers mentioned in "linleHP"'s note. Installed those and everything is working perfectly again...