My nikon d90 does not have blur in the backround?

My nikon d90 does not have blur in the backround?
my old nikon d40x had that feat but my nikon d90 does not have blurry backround?

Could be you need to read up on the Basics of Photography for bokeh.

You really need to take a basic photography class. Blurring the background is done through a combination of lens aperture, distance to subject, and distance to background. It makes no difference what camera body you are using…

You have been asking nonsense questions like this all day, It is clear that you have no idea how to use a DSLR. Either sign up for a class or buy a point and shoot.

Return it to the store at once. You have probably been extremely lucky with your D40x. It doesn't have one too normally. It would be best to exchange your camera with a disposable one.