I added 3TB Seagate hard drive to my a few years old Dell XPS 8300. Windows 7 took more than 10 minutes to start, but failed to detect 3TB Seagate hard drive. I saw many people here said 3TB Seagate shows 746GB or something, and then they may use "DiscWizard Software" as Seagate website mentions, http://www.seagate.com/support/downloads/beyond-2tb/
But in my case, I could not see the new hard disk at all. Any ideas?