[N3WBI3]

Really? at the system registry level? Linux and Mac prevent user accounts from mucking around with the global libraries.. In addition they come *with* a firewall, you dont need to install third party software to get one..

[discostu]

Windows can be setup to keep user accounts from mucking with the registry and system folders too. Problem for all three OSes is that if you want to install software you're going to have to do it from an account that has administrative priviledges, once you're in that mode they could piggyback spyware. That's how most spyware gets in: while you're installing something else.

[xrp]

Windows XP has a built-in firewall.