Originally Posted by
smargh
Throw away NIS, install Microsoft Security Essentials. Ensure Flash is up-to-date, do an initial scan with Malwarebytes & perhaps pay for the cheap one-off lifetime license for resident scanning.
Ideally also install Firefox with AdBlock & NoScript and teach them how to use it. My sister & mother are happy with FF+NoScript+MBAM+MSE and have been malware-free for a few years now.
For a dumb family friend I did need to set up XP with SteadyState because he clicks on everything.