When I try to open Photo Gallery (Windows Photo Gallery 2012), I get error message:

"Photo Gallery: WLXPhotoGallery.exe - No Disk
There is no disk in the drive. Please insert a disk into Drive E:."
with the options Cancel, Try Again, Continue.
At that point , none of those choices lets me get out or continue, and I cannot get into or close Photo Gallery.
The only thing that lets me continue is to put an SD card (any SD card) into Drive E, then Try Again gets me in.  Then I can remove the SD card with no apparent problems.

As background, Drive E is my SD card reader.  I normally take my SD card out of my camera and put it into this drive, then, outside of Photo Gallery, copy my photos to folders on my hard drive.  Then I use Photo Gallery to edit and email photos.
This problem just started happening with my latest photo upload.  I since deleted all the folders and photos from my hard drive that I just loaded but that doesn't help.  Apparently Photo Gallery is still looking for something on Disk E but I don't know what or how to change that.
The only thing I can think of that I might have done differently this time is that instead of dragging my photos from my SD card to a hard drive folder directly, I selected them on my SD card, did Copy, then did Paste onto my hard drive; but I don't know why that would cause any problem.

If there's no way to fix this, are all my tags, etc stored in the photo files, so I could try uninstalling Photo Gallery and re-installing it and keep the data?  But I wonder if that would even do any good.

And off-topic but how does Photo Gallery fit into Category Outlook.com,Skydrive?

I'm on a desktop with Windows 7.