I have reason to believe that my dad has blamed me for the crashings of 4, yes FOUR computers.Will you help me?

i know that he has a history of a addiction, due to the fact that "teens.com" is not a college info or a game website. he used to not work, and he obviously had nothing to do. i believe that he is doing the same on this computer because i checked the temp internet files and there are some instances of it. he told me not to download anything, but i have a 128mb flash drive i got from my Friend. is there a typo, or a log creater that can run from the flash drive, and that i can hide? i know how to hide folders and stuff, but i know most programs show up in the task bar, so is there a program that is private? i need something to show to him, so i can make this computer more accessible by me, and my mom.