Then it's likely the connector on the main board has failed. As you are a computer repair tech you know to pull the board and see if you can touch up the solder work and re-try one last time to avoid replacing the mainboard.
I discovered an obvious bad HD, bought replacement and cant get the computer to see the primary HD at all.I switch them around old and new in the 2 spaces but the bios only sees the one that is in the 2nd space.dv7 1175nr with 320gig black WD, and purchased a 250gig blue WD. Also I just went in the BIOS and there is very little you can do from the configuration section,just boot order from what I see.You can run tests on the secondary discs,but not the primary,no matter which one I have in that bay. Any ideas? Thanks, Mark