Graphic Program not working properly

[Goldilocks]

My desktop computer that I use for my photo work has been giving me unsupported file type in various graphic editing programs making using my programs unusable. In ViewNX jpg will not display and NEF will not display when I attempt to edit. The NEF file (a Nikon propriotory raw file) is from my Nikon D5000 camera. I recently moved to a place and do not have internet service there. I am not sure what the problem is, nor how to go about trying to resolve it without direct internet service. I have not been using my computer for a couple of months due to my living circumstances.
 The last checkpoint stored (before a bunch of Windows Updates checkpoints on various days throughout the summer) is in June. I'm not sure if that is the best first line of attack.
 Maybe some kind of file or program that understands nef (is that a codex?) is corrupt?
Any and all suggestions would be helpful. In order of safe, wisest approach first.

Also, when I am in lightroom and go to develpe it says unsupported file type for DNG and jpgs.
 
If you know of anyone that might be helpful please feel free to forward this to them. It may even be something simple that I am just overlooking.
 
If you have a list of questions that I can take with me from the library's computer to home to help diagnose this, I would be greatful.
Linda

[sniper]

I'm no computer expert but for all your programs to stop "seeing" the various image files sounds like maybe the file associations have changed? or even the file prefix (the .jpeg bit) I'm sure somebody with more of a computer background can help you though.
What software are you trying to use and what operating system are you on? (vista, XP etc)
Wayne

[Goldilocks]

I have Vista home edition. The Nikon program ViewNX will display their raw file, but when I go to edit it, the area designated for the picture goes black and says unsupported file type. In the same program it will not even display the jpg saying unsupported file type.

Wheter it is the same problem or not, when I try using lightroom, it will not let me go into the Develope mode. It just shows that circle circling around and eventually says there is problem.

[sniper]

Have you tried opening an old photo, one you have already edited before? if it diplays that it may be the latest bach of pics have a problem.
Do the photos actually say .NEF at the end of the name? or does it say something else??
Wayne