Linux
Password protect,single user mode
The single user mode in Linux is considered the rescue mode,However ,anyone who gets physical access to the machine could easily change the root password by booting into single user mode.This is a security concern in Linux .So to password protect the single user mode ,add/append the following line in your /etc/inittab file:
su:S:wait:/sbin/sulogin
Now ,whenever the system is booted in single user mode.it'll first prompt for the 'root' password

How to Remove the Recycle Bin from the Desktop?


If you don't use the Recycle Bin to store deleted files , you can get rid of its desktop icon all together.
Run Regedit and go to:
HKEY_LOCAL_MACHINE/SOFTWARE/Microsoft/Windows/CurrentVersion/explorer/Desktop/NameSpace
Click on the "Recycle Bin" string in the right hand pane. Hit Del, click OK.

How to make your Desktop Icons Transparent?


Go to ontrol Panel > System, > Advanced > Performance area > Settings button Visual Effects tab "Use drop shadows for icon labels on the Desktop"