Adobe Illustrator will not open any PNG images anymore

Illustrator has stopped letting me open PNG files. I never had an issue before until maybe a few days ago. I've tried every way I can think of to open it; right clicking on the image in the desktop, file open in illustrator, etc. No matter what I do, the file just will not open. Illustrator doesn't even give me an error or anything, the image simply just does not open in Illustrator.

Moderator Note: Moving to Illustrator forum for more specific help.