No Access to Computer

Hello,

My name is Michael Carnahan, but you can call me Mike. The reason I am posting this message is because my friend Chris has a problem. We both have a Mac Book Pro but his is a little older than mine. Anyways at one point it randomly stopped working. He turned on the power like usual except it had the apple icon and loading circle. After a while of waiting he realized something was out of the ordinary. Therefore, he went to me, one of his friends that was well experienced in the Apple department. So after some reseach I found that it might be an update problem and was the closest match to the error screen/image on the desktop based on the websites info. So I follow the procedures for that it told me to turn the computer off. Then press the power button and right after hold down shift. It didn't provide how long I was supposed to hold the shift down therefore after 30 second I let it go. It said on my computer it would put it in Safe Boot/Mode. Shortly after releasing the shift key a loading bar appeared. After 30 minutes to 1 hour of waiting it was fully loaded unfortunetly neither of us were present toward the screen at the time. And it automatically shut the computer off so I can't exactly explain what happenned after it was fully loaded. So I thought it worked. After turning it on I saw it brought me to a grey background with a power button in the back with coding in the top right of the screen and said to restart it. I was pumped I fixed it without spending any money. But this happened again and again. Therefore we had no access over the computer. I don't know how to recover the computer. If you read this far I thank you for reading and giving your time but I need to know two things before you go. One, what the problem is and two how we can fix it. I am looking for the cheapest if possible freest easiest way to do so. Thank you for your time and as always have a great day!

-Mike