No bootable device error, can\'t start computer

first, check the cables/connection, sometimes they are just loose.
make sure that it is connected properly.

if that does not solve it, then there may be a problem with your hdd. try another hdd or remove your current and try it on another pc.
 

Yanaishere

Honorable
Jan 13, 2013
12
0
10,510
I am 99% sure replacing cables will fix the problem.

Once I faced a similar issue. I installed windows, did this, did that and then I finally spared thought that it might well be a hardware problem. Bingo!