It seems, after quite some hassle, I did come back to your original suggestions. Sorry that I couldn't do so earlier, but frankly speaking, I couldn't have fully followed your instructions and don't know why they are relevant (still don't understand why a motherboard would matter), thus I had asked for your explanation on my issue. After trying and error and spending more money and gaining more knowledge, I finally found that yours might really be where the issue is.
Now I am trying to upgrade my display driver with the latest I could found (2013?!). For the monitor, it comes with no installation disk/driver. I checked with amazon where I purchased it and they told me that most likely it is automatically installed through windows update, which is an issue for me as my computer does not have internet. Another issue I am concerned is, could it be that the computer cannot detect which port it uses to send video signal? Would this be a valid concern?
Thanks,