the siding of my 1940 old house is cement, I want to buy new ones to replace some or try to fix them..?

the cement boards are ahold by 1 nails

Hardyboard is a composite/concrete siding that may work. If your boards are only slightly damaged you may be able to patch them with concrete patch then repaint. A lot cheaper than replacing.

those are probably asbestos! caulk the damages with acrylic latex and paint.