Mb wont post or even give option to get to cmos

I install motherboard into case install memory in just channel b says the book, install pci express board or any video card the system spools up but will not post and there is no screen messages at all screen is blank the screen is acting like there is no power being sent to show association to the mb and that is so with any video card including a simple 2mb pci card. PS is a 450 ss mem ive tried 3 different sets with no luck