You're going to laugh at this, but believe it or not, I was like 10 when I came up with this name and it stuck for some reason, everyone knows me by it. But yes I am a fan of Slash, the guitarist, but no, the name was not based off him. I liked the word "slash" as in "slashing" thing, and put fan next to it lol. Then the 7964 was an attempt at finding the center of the number pad (above letters, not the calculator styled one to the right) but since there is 10, there is no center number (set of 5 and 5, nothing in between since it's the same number) and went to the right 2 spaces, then back to the 7, and then chose 6 so both middle numbers of the keypad are there, then left 2. 7964.
Short version:
I hit the middle of the number pad then went right 2 spots, then back to 7 and picked 6 next to it to get as many middle numbers as I could (5 wouldn't fit, didn't seem right) and then left 2 spots. I liked slashing things so I said slashfan. slashfan7964. Changed it though when I went premo to just Slashfan, but wanted Slash. UGH. SF was taken too.