Windows Defender

I like it!

easy to use, runs quietly, not a resource hog, free

easy to use & runs in the background.

this damm program and the firewall you just dont need them
since i bought my laptop over 1 year ago, ive had 0 virussus
install avast anti virus scanner and thats all you need for a clean pc

Does it realy defend any thing? It has never done any thing for me ... or at least I dont know about it.

I really don't like it.. it gave me many hours of frustration when I didn't know why my comp laggs for no reason...
- it's just hogging in the background...

Just started it to turn it off. This software does not find a lot and slows the system down.

Windows自带，从来没见起效过，经常更新

defending my windows vista

with combination of classic antivirus it's useful because most of antivirus SW doesn't let you know eg. when something is changed in startup applications...

This is just one of them default things, I wouldn't trust it to block viruses. It's better than nothing I suppose, good for people who only use the internet to check their email, but not many DO that. So I would NOT suggest using this unless necessary.

does its job, not bad

Well comes with windows, it does the job, but updates through auto updates unlike avast which just updates, in a way Vista is a pain in the arse.

Very good ant spyware in windows, found many maleware that other security software unable to find them

wtf do you mean its not free? It comes with windows dumbass.
Never catches a thing anyway.