I was working with my laptop containing a SATA seagate 320GB hard drive 4 days ago and windows stopped working and was frozen. I restarted the laptop but could never get it to work again and it gives me "No OS Found" error. I wanted to reinstall the windows but windows setup doesn't see my hard drive(my bios detects the hard drive with unknown size!). So I connected the hard drive to another computer running windows vista and ran the disk management from computer managemenet. It sees my hard drive but it's Unreadble and Unknown containing a red "!" mark on the drive icon and i can't do anything with drive there. Imean when I righ click it I have no option but "Help". I also ran the Seatool diagnostic program from seagate and all of the tests failed. But I'm wondering if all of the tests filed wich indicates severe hardware failure how does bios detects the hard drive? Couls it be because of the faulty partition tables or MBR os something like these?
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He didn't really read your question... The answer is that all hard drives have a drive controller card on them. So yes, even if your drive is bad the BIOS can still tell that something is connected to that cable even if the data on the actual platters cannot be read.
Previous posters are both right. The mere fact the BIOS can detect there's something alive! Igor! out there offers little hope. You could try asking Seagate Tech Support if the exact results of the Seatools diagnostics tell them anything about what is broken and how to fix, but I doubt there is very much that can be done. So if you REALLY need the data, r_manic is right about a pro recovery service - and prepare yourself for price shock!