From the above picture,you must konw is Dell computer's PSA self-test program.

PSA: Please shutdown first,  press and hold on FN , then use your another hand to start the computer and then release both hands, the computer will enter a blue screen test and you can see the color bar.

When you see color change Laptop Screen, it is testing the computer screen, click the Y button. And then the computer will appear CPU detection. If the computer have failures, the computer will alarm, if there is no problem, the computer will pop up

And there will be a tips as "No problem has been found with this system so far "!

This is the way how to start the PSA, however,if there is an error, you can refer to the above pictures, then you can accurately know the laptop tips causes of the error!