It's really hard for me to believe someone I don't know. It's even harder to believe someone when they plead that their story is true. That only makes it seem like you are forcing your way, that in itself makes it hard for me to believe you. (I should know, I went down this path myself, and still regret it)
And even if you ARE telling the truth, then you share the blame, not just your brother, for leaving your computer on EVEN THOUGH you know your brother causes trouble for you and others (judging from your bio)