I just bought a new CO2 tank and regulator. This is my first experience with kegging and I was psyched. I thought I put everything together ok, but I cant seem to get the CO2 tank knob to turn on. It wont budge. I hope that I am just doing something stupid, but not sure if anyone can help. I wont be able to get to the homebrew store until Saturday and would like to get this resolved asap if possible. Any thoughts would be great.