Picture is not clear in the viewfinder

While looking through the viewfinder, turn the little knob at the upper-right corner of the viewfinder to adjust it.
Refer to the "Adjusting Viewfinder Clarity" subsection of the "Basic Operation" chapter of the manual (page 36 in my copy) for full details.

Many cameras that have view finders do not support use of the LCD display to compose or frame a picture. This is generally to conserve battery life of the camera. Most of these cameras limit how long a picture is displayed on the screen to 10 or 15 seconds, immediately after taking for the very same reason.

The exception would be a camera that lacks a view finder - or has a menu item that allows the user to compose the picture on the LCD in addition to the viewfinder. Some manufacturers call this "live view". Check your camera manual to see if it is supported. If so, be sure to buy extra batteries!

I hope this helps & good luck!

Your camera is equipped with a optical diopter that will allow you to adjust the optics in the viewfinder to your eye. meaning bringing everything into focus as it should. The way I use this (set it) is to let the camera auto focus on a subject and then turn the diopter until I see the subject clearly.
It really helps if the subject is about 12 feet away (get it real sharp) and the camera is mounted on a tripod. Once set I put a little dot of paper white out on the diopter adjustment knob so if it gets turned I know and can quickly return it to the correct spot. I'm including a diagram where this adjustment knob is on your camera, have fun.

Diagram

Pls. turn the little knob near the finder untill you get clear picture inside finder, previous owmer might have turn the knob for his eye sight good luck.

Adjust view finder focus as you will see setting there, to view correct focus in view finder itself.
Camera is just fine because it is taking good focus pictures.

What you're describing is a feature called "live view" (or more accurately "live preview"). It enables the user to treat the LCD like a viewfinder to compose shots just like on any digital compact camera.

Although many newer digital SLR's now have live view, the D60 does not so you cannot achieve what you want. All that the LCD is for is to view photos already taken and to provide camera menus and information in all other modes. Composing the images before pressing the shutter is done solely via the optical viewfinder.

You should go into the menu, camera settings and set the evf to on. EVF stands for electronic view finder. This can be set to be on when the lcd is open or closed. CAreful, if the evf is set to on and you point the viewfinder towards the sun, it will burn white marks into the viewfinder and ruin it.

Ok. On your viewfinder, there might be a round dial. Turn it to adjust focus. Otherwise, sometimes viewfinders are like that... blurry, especially electronic.

Turn the small dial to the right of your view finder either "+" or "-" until picture is clear inth eview finder

Some digital SLR camera have a mirror lock and others have a viewfinder shutter In each case this will be a knob in the region of the viewfinder that turns. Check that this model has it and it has not be inadvertently turned. Then come back