Computer will not boot windows.

[Awwab]

I have had this computer running fine for almost a year now, I did a routine restart and the system would not load windows anymore. I can get through the bois/post fine but then all I have is a blinking "_" and then black. I have tried switching out the following parts with no success, Video Card, RAM, HDD, Cables, PSU, and Monitors. The hard drive will boot successfully when in another computer and I have tried reinstalling Windows 7 on it. I am really at a loss as to whats going on so any help or things to try would be great.

 

[Niklas_13]

Try to reset the CMOS on the mobo

 

[Awwab]

The CMOS reset did not work, left the batter out for a few hours and nothing changed.