Today something happened with my mac computer. I was working with no problems, then I went for a cop of coffee and when I came back I found a black screen and a very faint form asking for my password (It was really hard to see that form). so I try to press the power button that nothing happened. I pressed it for like 10 seconds (as I used to do with my windows computer) and it seems something sounded but I kept getting the black screen. then I decided to plug it in and and plug it out and for some reason it worked (the battery was at 57%), but it seems it restarted but itself because I was prompted to enter my mac password.
I have no idea what happened, but of course it closed all the programs that I was working on..
Not sure how to check it is have a virus of a hardware problem. Could you please help me to troubleshoot this issue?
Thanks in advance,