So, most of your images are saving as Untitled, even if they do have a file name.
First thing you can do is to clean internet related stuff:
Delete all temp files, coockies, temporary internet files, etc.
But, for a better clean of that stuff, download CCleaner from here:http://download.cnet.com/ccleaner/
, install and run it. Then restart your PC and try to save an image.
It helped a friend of mine in a similar problem...so, I'm almost sure it will fix yours...