I have built 9 new computers for my office. All with the exact same specs:
MSI 760gx 20 AM3+ MOBO
8 GB DDR 3 Corsair RAM
AMD Athlon II x4 3.0
OCZ Petrol 128 GB SSD
Most of the units work well, but 2 of them allowed me to install Win 7 and worked fine for about 2 days, then when booted up, would tell me to select the boot device and restart.
I have changed all of the settings I know of, and tried all SATA ports, but there is no luck. I have booted in to Windows recovery and that won't find the disk. In the BIOS settings, it doesn't appear there as well.
Anyone with any ideas? I have tried plugging in another drive, and even the new drive doesn't show up.
When you plugged in the other drive, did you remove the OCZ drive from the system? If your mobo no longer recognizes any drive on its SATA ports, you got some bad mobos. If you need to replace them, I would suggest Asus, ASRock, or Gigabyte ahead of MSI, especially at the low end.
You either have bad motherboards or SSDs. Remove the SSDs first, swap in a different drive (an old reliable HDD works best for testing) and see what happens. If all is OK, try the suspect SSDs on another PC. That should tell you which components you need to exchange.