Invisible disc in dvd slot

I have a mid 2009 17" macbook pro with latest MacOS.
When I try to insert a dvd in the slot it won't go in, but gets resistance similar to as if there was a disc in there already. However, I'm am pretty sure there is no disc in there. I have no memory of inserting one and it doesn't appear on neither the side panel nor in disc utilities. I have tried all eject methods incl rebooting. I even tried opening dvd player.
Anybody recognize this? Is there another way to check if there actually is a disc in there without taking the machine apart?

Anders

You should be able to turn the machine on its side and hold the slot open (you can use most anything - but make sure it doesn't go inside); then shine a flashlight into the slot. If you still can't see anything, you may have to take the drive out as it may be defective or there's something stuck inside.

Removal instructions can be found at www.ifixit.com.