No need to reinstall the operating system. Go to Start/Computer. You'll see System Properties at the top in the blue bar. Click on that. Remote Settings will be in the blue panel on the left. You'll have to provide an Administrator password. Under Remote Assistance, uncheck Allow Remote Assistance connections to this computer. Under Remote Desktop, set it to Don't Allow Connections to this computer.
1) Don't leave a bunsen burner on when you leave the room. That's how you burn down a building. 2) Don't let it be so hot for so long that it burns out all your reaction liquids, and so you start burning glass. 3) Keep alcohol away from the Bunsen burner. 4) When you are doing most syntheses, put the burner or hot place in a fume hood as you conduct the chemical reaction because you need the fume hood so you don't inhale chlorine gas or whatever gas is released from the reaction. 5) Wear safety goggles, make sure there are no gas looks, and turn it off when you are done.