This has happened to me with two different laptops. I'm fixing an HP laptop that after POST, when loading windows, it shows a blue screen error and then, it restarts again. Everything is fine with the tests on DOS, but when I do the Long Hard Drive test, it takes a very long time than usual, and the results is that all tests passed, I would believe that is just the OS being corrupted due to a virus maybe or is this really a HD problem? Im using PCD 7.5