Minecraft has strange lines in the graphics?

I now have a new PC and when I downloaded Minecraft, there were strange looking contours around all the blocks. Does anyone know what this is and how I can get rid of it?

Greetings and thanks in advance

Commander1215

(P.S. I uploaded a picture of it in the attachment)

Do not understand what you mean. Possibly uninstall the Texturepack?

Look in the control panel of your graphics card for the following settings and turn them off or on:

Mipmapping
Anti-aliasing
Anisotropic filtering