Shortcuts are good to know if you use computers a lot. Especially they help to reduce the mouse movement which is very important if you suffer from the Carpal Tunnel Syndrome.
I just read this article from Lifehacker and I found these shortcut really great! I never knew that there are shortcuts for these kind of everyday tasks. I love these shortcuts.
- Win+R: shows Run dialog
 - Win+D: toggles Show Desktop
 - Win+E: starts Windows Explorer
 - Win+L: locks computer
 
If you use Firefox , below shortcut are useful too.
- Ctrl + L : brings focus to the location bar.
 - Ctrl + K : brings focus to the search bar.
 
LifeHacker: Make Windows More Productive Without Installing a Thing