Problems adding pictures

I noticed last week when i was trying to insert a picture, I clicked on the Add media, add and image. As always the box popped up where I can browse for images (Chose file to upload). Well now when I click on the Choose file to upload, before I could browse for pictures, now I can not. Any ideas on what this might be. I did hear about this happening with someone else where it didn’t work on one computer, but it did on another computer. Then after some time it stop working on both computers. There were no repsosnes back, so not sure what happened there. Any help would be great.