Now-a-days security checkpoint officials may ask you to start your laptop to show that it functions normally. You must be aware of the time your laptop requires to logon.

So, if you plan to take your laptop with you, start your computer well before you are in the security checking queue and ensure that its battery backup is sufficient and don't turnit off. Keep it rather in "suspended mode" or "sleep mode" and put it in your computer bag. Now at security check point it will start just in a few seconds. After checking you can shut it down.

The Transportation Security Administration recommends that you paste a business card or an identifying card on your laptop to assure that you walk out of the security checkpoint with your own computer - and no one else does.