How to get back the default settings in my nikon camera?

I have a nikon dx af-s nikkor 18-55 mm vr camera. I almost know nothing about it. But one of my friends has changed the settings and when i take a picture i find that the picture is getting blurred. So is there any way to get back the default settings of my camera back or is there any other way to resolve this problem.

There's a factory default reset, both in your cameras menu and what is called a two-button reset. The two buttons are green.

You really need to read your user manual. Blur is caused by using too slow a shutter speed which can be caused by so many things, you really need to learn the fundamentals of photography to be successful using your fine camera, what ever it is.

It seems that you have been using the camera like a high quality, expensive P&S camera, letting the camera do all the work for you. Take control

NOTE: It is NEVER a good idea to let friends use or handle your camera, especially if they like to tweak thing

You don't give us the Nikon model number, e.g., D3100. You give us the lens id. Like it has already been said, Nikon has a two button camera reset, the ones on my D90 are marked with a green dot next to each one. There's also a menu item to do the same thing. I hope you are enjoying your camera and let me encourage you to learn more about photography with a photography course.