Why do pictures on my Nikon D3000 come out slightly blurry?

I've had my Nikon D3000 for about 8 months and it has been working completely fine until recently, when the pictures started to get out of focus (blurry on the edges like everything was reflected out of a mirror, kind of like motion blur, or weird everywhere). I lost the cap to the lens a few months ago and I thought that might be the problem but it isn't likely since the pictures have been fine until now. I have tried to reset the settings and everything but it just isn't looking like it will work--is it something I did to the settings?
I would really just like pictures that are worth as much as the camera! I'm really dissapointed.
Hope some of you techies can help!

I would say it's not the settings since they have nothing to do with focus.

Have you tried another lens? If not that would be my first recommendation. Second, if that doesn't help, I'd suggest you call Nikon, if it's still under warranty. Un less something has happened to the lens, dropped or otherwise damaged, I can see what else would be wrong. Call them.

Look on the front of the lens, there might be scratches/dust on it.

Clean the front of the lens then take off the lens and clean the inside of the lens and the inside of the camera. That should help but try to find a new lens cap for your camera because you really do need one

Could be anything.

Your shutter speed high enough?

Using a tripod but with VR turned on at the lens?

At any rate turn VR off at the lens and try it. It might have gone whacko.

(your lens should be a 18-55mm VR).

Have you been shooting in the dark lately?