When I am trying to align the z axis I used to hold ctrl while moving the mouse and having the middle mouse button pressed down.
Now that does not work properly for what it used to do.
Pressing b to get a selection box and than pressing b again to get a selection ring does not work.
And i did something that made the object disappear by hovering of the add>mesh menu but I can’t do that one again and again and again so I am just scared of it ever happening again.
Now some tips: If you want to move/rotate/scale along particular axis you can:
press G/R/S to choose transformation
now press X/Y/Z to lock to a particular axis
move your mouse to transform
Now CTRL key only makes your transformation in larger steps, and SHIFT key gives you finer control. You can’t really use it to do alignment.
Regarding your aligment question, I suppose you want to rotate&move your object so it sticks to some surface? There’s a snap function (magnet icon in 3D view window bar), but it isn’t always working like expected. Insted you can try to use following functions to help you position your object:
Press SHIFT+S to bring the snap menu. You can use it to snap your cursor to selected object/vertex/edge/face, or the other way around - snap the selected element to the cursor’s position. Use “Cursor -> Active” to move cursor to the currently selected element.
In object mode, select your object and press SPACE and select Transform > Center Cursor to put object’s center in cursor’s position.
On your 3D window’s bar you have a Pivot menu in which you can select pivot for object rotations. Set it to Active Object. It will now rotate the object around its center.
Using above mentioned techniques you can align your objects with relative ease. You still have to do it manually, but really a proper use of pivot point and cursor snapping is the key here.