I gained a Raspberry PI board. I want to dive deep in it's programming, but I've faced a disturbing problem: After booting automatically displayed a PDF. I can close it, but I don't want to do regulary, I would like to remove of its boot seqeuence. Where can I do it? I checked the .bashrc file, but it doesn't include reference to this. I found the PDF file, but I'm afraid, if I'w delete it, it would cause issue during boot process. Does someone has any idea? Thanks in advance!