I tested it successfully on FireFox, Chrome Plus and IE ^^ and I guess It works perfectly on other browsers .
This hotkey is very useful for lazy person like me .
When I am browsing a website, for example eyesfall.blogspot.com and I want to go to Google.com , as usual I need to select all text on my address bar, delete it and type Google.com .
but I found out that I just need to press F6 to do that .

Try it yourself !
Start -> Run -> Type CMD and hit Enter , a new Windows appears : You've just opened Command Prompt .

Type anything you want, like "ipconfig" to view Ip configuration of your comnputer ...

If you want to clear your black screen : just type cls (it's not case-sensitive, don't worry) and hit enter . Enjoy !
When you go out and don't want to re-open your data, program...
Hibernation is a good choice, it saves all data in hard disk when hibernating and recover all of them into RAM when start-up.

To use it : Start -> > (right arrow near Shutdown button) -> Hibernate .

If you DON'T SEE IT :

Step 1 : Start > Run > CMD , hit enter : in command prompt type : powercfg -h on

If you still don't see Hibernate button, go to step 2 :

Step 2 : Start > type "power " > and click on "Edit power plan" ABOVE
Click to "Change advanced power settings" > Expand + in "Sleep" and make sure that "Allow hybrid sleep" is OFF .