X51 gtx760ti blank screen in bios and dos / before enter Windows login page.

Hi,

I have x51 2013 with gtx760ti.

My problem is my monitor will always be blank whenever i start my computer. After few minutes, Windows login page will appear on my monitor, hence i am not able to access bios nor view any information in dos mode (for example select boot mode etc).

At the beginning it was working fine. I was able to view bios configuration and even reinstall my Windows 7 with retail version (i bought this computer in China which came with Chinese language, so i need to reinstall English version of Windows). 

However after few months, my monitor will be blank during startup until entering Windows login page.

I have tried with multiple monitors and the same can always be reproduced. So far the issue can be reproduced when using VGA monitor (by using DVI converter since my computer doesn't have VGA port) and HDMI.

Now the problem is I tried to upgrade my Windows 7 to Windows 10 and forgot if i have this issue. during installation, after my monitor blank for few hours, i tried to restart the computer by holding power button for few second.

Now i think my windows is corrupted and no longer can be boot and i may need to reinstall it. However since i cannot see anything on my screen, i cannot even reinstall the windows.

I suspect if the issue could be related with graphic card, but seems the port to use on board hdmi is no longer available for X51 2013.

Appreciate any suggestion to fix this issue.

Thanks.