You can check this easily using a multimeter (if you have it) or even using a flashlight bulb and a flashlight battery.
IF you don't feel comfortable doing this don't do it. You proceed under your own responsability if you do something wrong.
FIRST :
Disconnect the power cord from both the equipment and the wall. Just put your multimeter for diode testing or continuity and put one test lead to the third (round)pin in the "male end" and the other in the middle slot in the female end. If you get continuity you have a grounded power cord.
You can do the same using a small cable piece the battery and the flashlight bulb. I think you get the picture and should be easy to do. i.e. round male pin to battery bottom (-) put bulb to battery (+) and small cable from middle slot in cable female end, touch the metal part of bulb, you get light there's continuity therefore grounded cable