HDD causes my computer to not start

[321patrick123]

In my computer I hav a 64GB SSD, a 250GB SSD, and a 2TB HDD. I turned on my computer and my whole screen was black and it said " A2 " (without quotes) in the lower right corner of the screen. I unplugged all USB devices and then all i got was a black screen (yet the monitor was still illuminated). I opened the case and unpluged the data cable for the HDD and my computer worked, only I have my profile stored on the HDD so the profiles failed to load but windows seemed fine. I reconnect the HDD, turn on the computer, and all I get is a black screen. I reconnect my USB devices and I get a black screen with the A2 at the bottom right of the screen. Please help me I have no idea why my HDD is making my computer not work because it worked perfectly fine yesterday.

PC specs:
OS: windows 7
Motherboard: msi z87 g45 atx
CPU: intel core i5 4670k
RAM: kingston hyperX blu
PSU: corsair RM 750
GPU: Radeon r9 290
HDD: seagate barracuda

 

[Phillip Corcoran]

The HDD may be faulty. Test it with SeaTools for Windows (tests any make of hard drive):
http://www.seagate.com/gb/en/support/downloads/item/seatools-win-master/