The right way to sit at your computer
What is the correct stance while sitting
First of all, you need to have the top of your computer monitor at or just below your eye level. Then, keep your head and neck in-line with your torso. Now, keep your shoulders relaxed. Keep your elbows close to your body and supported. Lower back supported. Adequate room for keyboard and mouse. Feet flat on the floor.
How Not to do it.
Monitor high above eye level. Feet sprawled on the floor, and body slouched over the keyboard.