Using the delete button on my keyboard

Hello! Has anyone else had issues with trying to delete objects in SL and the delete button on the keyboard doesn't seem to work?

I installed parallels onto my mac laptop and then installed Windows. I am running SL on Windows. I ran SL and inserted a ppt. I tried to delete the objects on one of the slides, but nothing happened. Is there a reason for this? My delete button works when I am in ppt, just not when I am in SL.

Thanks.