Why Dwhelper folder in my Mac Desktop

Holy Mary Mother of God.... After this is over, promise you will set up a limited account for others, with parental controls, and make your computer sign off or start the screen saver after 10 minutes of activity and require a password to wake it. Okay, as a parent myself, I do know kids are VERY cool and very inquisitive... and stuff happens.

Okay, first, your Macintosh HD should have a Library folder there. If it is there, The library folder you see belongs in Macintosh HD > Users > Your Name, along with the following items:
Applications
Desktop
Documents
Downloads
LIBRARY
Movies
Music
Pictures
Public
Sites

The Library folder you see there PROBABLY was from that folder, and the Documents folder you see in that Music folder belongs there, PROBABLY, as well.
The Macintosh HD should have the following:

Applications
Developer (maybe not installed, not all that important)
Library
System
Users

Moving these folders around MIGHT cause you to get an overwriting warning, BECAUSE your preferences WILL be written to where they need to be written to... Okay, this might be kind of confusing, so the BEST idea is to somehow back up all this before you begin.
Start with that.

 

Another thing you can do is set the screen saver to activate with a hot corner (I use the bottom left) and set the option for Require password to wake this computer from sleep or screen saver under Security. This way if you're going to be away from your Mac you can just put the mouse pointer in the hot corner activating the screen saver and password protection.