You can reduce mousing by using keyboard shortcuts. As just one example, with Windows programs, you can typically press the Control and S keys to save a file instead of moving the mouse pointer to the File menu and selecting Save. Ergonomic chairs that are adjustable in multiple ways help prevent back problems. But I still regularly bruise the discs in my lower back from sitting too long. What works best for me in preventing this is remembering to take breaks and stretch, keeping my stomach and back muscles strong through exercise, and having my back massaged at the end of the day.
Eyes are another common sore point when computing.
There has never been any conclusive evidence that radiation from computer monitors leads to health problems. But staring at a computer screen can cause eyestrain and, because it is a form of close work, can worsen nearsightedness. My own glasses have grown considerably thicker since I bought my first PC nearly 15 years ago. Experts say your most eye-friendly moves are to stay a foot and a half away from the monitor, minimize screen glare by positioning external lighting to the side, and periodically rest your eyes. Computers are great when they are not a pain in the neck, the back, the wrists, the eyes . . .