I usually got headache after staying upto 5 hours in front of the Computer..

hai, yah it is a genuine problem,after passing much time on any bright thing uwill feel pain either in eyes or on head,i have similar problem but it is in eyes,i take some rest and face my eyes with cold water.

It'sbut normal to get headaches if your're staying that long in front of the computer, it's called stressed eyes. THis occurs especially if you're just new to the habit. The only thing you'll do to prevent this from happening is to minimize your exposure to computers, not until your eyes get adjusted to it. You may take pain relievers (analgesic, paracetamol, ibuprofen) if it recurs.

There are several reasons for it. Perhaps you just strain your eyes too much because you switch sites too fast and too often. Perhaps you're too near your monitor that's why sooner or later your head aches. But the most definite thing I could think of right now is maybe you have eye problems, you need glasses. I experience that too several months ago. Before, I could stay in front of the monitor in long hours, but several months before I could find myself having severe headaches after just 2-3hours in front. There are even days where a few minutes would cause me a lot of aches. I thought I only had migraines until I visited the Ophthalmologist. There I found out I had eye problems. Now, the headaches and eye strains are gone. I'm now wearing glasses. Perhaps that's your solution as well. Good luck!