Ive had this problem once before. I turned my PC on Yesterday, and my WD 500GB Hard drive (Number 3) was not recognised. Then I did a reboot, and the drive showed up again, HOWEVER, The drive has the Read Only flag in DiskPart and using the attrib disk clear readonly commands with the correct disk selected does not work. DiskPart just moans that It cant clear the attribute.
Any suggestions are welcome & Im willing to try anything. I doubt its a Driver
Issue or a Hardware issue as It was working fine.
All the tests in Ubuntu 10.04 (my second os) come up good and I can write to it, So Windows 7 has done something, Not sure what.