Pressing 5 makes objects disappear instead of changing perspective

Support Basics & Interface
1

I notice there’s a layers tab on the left bottom corner, the number of which changes to 5. I want to use 5 as a hot key for changing perspective, any help?

2

Numpad-5 changes between ortho and perspective view. The “normal” 5 (below the F-keys) changes the layers.
If you don’t have a numpad, check “Emulate Numpad” in User Preferences (Ctrl-Alt-U) > Input.