I am not really knowledgeable to desktops, I just unplug and plug my GPU to clean dust then cannot start my desktop. Initially it just shutdown automatically, then I unplug power and reply GPU, after pressing start, nothing on monitor and flashing two yellow and 1 yellow. I check online and did some CMOS but does it work then I try to restart again, I can hear the sound but then just shutdown and power up again and again and again but still nothing showing.

Could anyone help please, I am updating my resume and really need it to be done soon.

Thanks a lot