I agree Mokoa. Windows XP was by far the best operating system I ever used. But, according to a friend of mine who worked in IT/systems security, there were a number of holes/bugs discovered especially in the past 3 years or so which leaves it very vulnerable to hackers and what not. Also, with Microsoft ending support for XP back in 2009 (or maybe 2010) it's only gotten worse.
It seems like I never had any hangups or crashes on XP, but Vista was absolutely horrible! Windows 7 doesn't crash too much, but there a TON of compatibility issues which makes it quite frustrating to use, such as the Malwarebytes issue.