Norton deleted all my program files, and other files are not opening

Till this day I had Kaspersky Antivirus. Today it expired and I decided to try Norton Internet Security. What an unimaginably terrible choice. Basicly my PC is $^#&ed. Upon installing Norton, I got a message saying that I have to uninstall Kaspersky first. So I hit *Uninstall* and norton did it. Then it said that I had to reboot. Very well. Upon restarting, I immediately noticed that my picture from user login screen was gone. I logged in and Norton was installed. I went to Start>All programs and there were only 7 things in it as opposed to, 30-40, which I had before installing norton. Then I went to Computer> Local disc c and noticed program files were gone, and the only thing remaining inside program files x86 was the Norton that I installed. My pictures and movies are in documents. They have not disappeared. However, they won't open. Whenever I try, a window pops up and it says "There was a problem starting C:\Program Files\Windows Photo Viewer\PhotoViewer.dll There specific module could not be found" Soo... What now? I am extremely frustrated and don't want to lose all my stuff here. Since the pictures and videos are here but not opening, I copied them to my USB. Will they open once I restore? If I can, that is. Or am I screwed? Please someone help me! I'm running Windows 7 64bit if that helps.