If the monitor has never been serviced, you may have to use a flathead screwdriver, Jimmy or a Heavy duty spudger. This will damage the plastic somewhat and is unavoidable. In some cases, you may be able to use a plastic pry tool instead of metal to avoid the damage, but not every time.

Open the monitor at the bottom of the monitor by releasing the four tabs with a flathead screwdriver or a Jimmy and plastic pry tool. If force is needed, the best way to do this is to put electrical tape on a flathead screwdriver and split the panels.