You can easily check your pulse on the inside of your wrist, below your thumb. 1  Gently place 2 fingers of your other hand on this artery. 2  Do not use your thumb, because it has its own pulse that you may feel.  Count the beats for 30 seconds, and then double the result to get the number of beats per minute.
It's not, LMB is Left Mouse Button. Its function can usually be replicated by the enter key.
The Scroll Lock key is a remnant from the original IBM PC keyboard. In the original design, Scroll Lock was intended to modify the behaviour of the arrow keys. When the scroll lock mode was on, the arrow keys would scroll the contents of a text window instead of moving the cursor as usual.