It won't make a difference turning off the computer. It'll just start the next time you do turn it on AND ONLY IF your computer is already infected. If your virus scanner, spyware/adware scanners, windows update, firefox and/or whatever else you use that has to do with the internet is updated as of march 31, you should be fine. And make sure whatever you download, you scan. One way to check if you're infected is to go on virus protection sites like Norton, McAfee, Trend Micro or AVG. If you're being blocked from them, you might be infected.
If you do all the necessary precautions on a regular basis, you really shouldn't have any problems. Viruses and worms are sent out by the crap load every day. I am hoping though it's an April Fool and just hyped up more than it is.
