objects not shoving

hey ive been having some problems with blender,
i’ts the 2nd time this have happend to me, and ive tried opening the problem on 3 diffrent computers, with no luck.

bassicly the problem is that blender decides not to show objects i add all of a sudden, ive made sure that they are not hidden or in another tap.

I can add an object and it will let me scale and move it, but i just cant see it.

hope someone can help:D

Are you in wireframe mode perhaps?
Press z to switch back to solid mode.
If that switches to another mode, then press D.
and choose Solid.