Which exact lenses are you trying to use? The N2000 (aka F301) is a manual focus camera so if you're trying to use autofocus lenses you have to focus them manually. Sorry if this seems an insulting suggestion, but you did state "my camera will not focus" and I've learned that on FixYa it's best not to assume any prior level of knowledge with regard to those who post questions.
The next thing to check is whether the viewfinder has an eyecup attached, if so slide it upwards to remove it as sometimes they have a corrective lens fitted if the previous user needed corrective optics. If your vision is fine (with glasses/contact lenses if necessary) then a corrective lens on the viewfinder may make things look blurry.
Other than that, the only other possible cause (other than a pair of broken lenses) is if the focussing screen has become dislodged downwards (or somehow fitted upside-down) then the viewfinder image will be unsharp. Officially the F301/N2000 had a fixed focussing screen but it could be replaced with one of three designed for the higher specified F501 (which does have autofocus), and if not seated correctly you'd get the focussing issue you describe.
You can test if the focussing screen is the problem in one of two ways:-
1. A visual inspection (you may need to get a more experienced photographer to take a look at it);
2. Set the lens to focus at infinity and at the widest possible aperture and take a photograph of a distant object (ignoring the blurred viewfinder). process the film and inspect the photo. If it's sharp then you have a focussing screen problem. If not, then it's a lens problem.
If the problem is a poorly fitted focussing screen then it may just need reseating or to be removed and refitted. It's vital to do this in a dust free environment and to avoid getting fingerprints on the screen. Some screens sit in a hinged frame which then clips into place when pushed up, others push into a pair of clips towards the top rear and then the front is held in place by a spring clip: it's been a long while since I worked on the F501 or F301 so I don't recall which system is used.
Courtesy of Norman Butkus' website, click here
for a free Nikon N2000 user manual.
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