About genuine microsoft validation problem

Hello,
today i installed windows xp in my pc and when i started it then i found an error message on the left corner of
desktop that windows did not pass genuine windows validation then i saw the suggetion on your site and it mention that go task mannager and end process of mghwhatever and i also rename it from system 32 so my question is will it dangerous to do this thing or i have to buy this genuine windows software but its very costly plz help me?