Veins bulge when my hands are aiming towards the ground but when i face them towards the sky it stops bulging. hands bulge a lot when using laptop?

Normal, probably: You are describing the normal physiologic process of vein drainage. When you raise your hands gravity carries the blood in veins back towards the heart without obstruction. When they are lowered valves block return of blood, and the veins swell. Likewise hands,when dangled swell because of lack of venous return -active use of the hands and their muscles will enhance the return.