Computer sensitive to static discharge

[grebsrof]

I have a problem with my computer. It is very sensitive to static discharge. It can freeze just because I touch the DVD drive. It even freezes at times when I leave my chair. When it freezes then the video disappears from the monitor. The board led may or may not turn off. Most often it is not possible to shut down the computer by pressing the power button (which in XP triggers windows to shut down). The computer is properly grounded.

I am out of ideas. What could make a computer sensitive to discharges?

 

[jsc]

How do you know it is properly grounded?

Just because it works does not mean it is properly grounded.

 

[grebsrof]

I have changed so that my wall sockets in the room are grounded. But of course the computer it self might have some kind of grounding problem.