Can you goto Manage tabs? its when you press the '+' button... can you unhide the my games tab?
Or have you actually deleted it?
*edit* if that doesn't work, you could try re-registering the products that dont show on the list anymore, with the register product button.
You will need the CD keys of the items you want back on the list, if you dont have them you can get them from the automatic email service from stardock.
hope that helps anyway, if that don't wokr you can always do the famous, un-install re-install technique ^^ my favorite, lawl.