I bought a copy of SimAnt and caught my sisters playing it. I didn't think it was fair that I had paid for it but they were playing for free so one of my dad's

I bought a copy of SimAnt and caught my sisters playing it. I didn't think it was fair that I had paid for it but they were playing for free so one of my dad's friends showed me how to rename the main executable and put a .bat file in that would check that the first argument matched an expected value (to "password protect" it)