You got a .rar file and you don't how to open it, some one asked you to send him "a rar file" or you just need a good archiving software? Download and install WinRAR.
Just like your Windows machine, Google’s Chrome has a built-in task manager, letting you see CPU usage, network activity and how much memory a site is using.
If for some reason your Android powered smartphone does not perform as good as it used to, or you want to sell it I suggest you to bring it to its original factory state.
For those who just got the new LG flagship Android powered smartphone LG G2 and are not quite sure where to start, here is the very basic what to do after I turn the phone on tutorial.