A friend of mine thought he could figure out my password on my computer and get into it without my permission. He went through the usual things that people would make their password, such as 'password' or their name, or birthday, etc. However, I have two passwords that I use for everything. One is a combination of seven letters and the other is a combination of four letters and four numbers. So, by this logic. To figure out my first password, and I gave him a hint, no letters are repeating, he would have 26x25x24x23x22x21x20=3,315,312,000 possibilities for that one. Then, there's 26x25x24x23x10x9x8x7=1,808,152, likelihood of him figuring it out before it said "fuck you" and locked me out of my computer for a little while.