As long as you keep your antivirus software current, you shouldn't have any problem. Microsoft is just trying to panic consumers into buying Windows 8 - which everybody I know who has it, HATES.
I worked with a computer just a couple of years ago, that was still running Windows 95 and it had never been attacked by hackers or viruses. Don't just click on any old dialogue box that pops up on your screen. Most of the people I know who have had trouble with things like that are the people who never stop to read anything on their screen - if it pops up and has an OK button it, they click OK, without any idea what they've just agreed to. Your best protections are common sense and suspicious skepticism.