So tonight I opened up a PowerPoint from my professor off that I downloaded off of the internet and I noticed a small black square in the lower left hand corner of all of his slides. I immediately assumed it was a dead pixel and ran the usual spectrum of tests and found nothing. This occurred on two PowerPoints that he had us download to read. Not once in my tests did this pixel appear again and I have never noticed it during any gaming or any other tasks (even when making my own PowerPoint I could not find this pixel) but when I open up his presentations again there it is. Is it even possible for something like this to happen?