I've just fixed the problem of Trustin by following the instruction here last night
Thx first~!

However, there is a Windows Security Alert warning me when I start up my computer today.
I've just scanned my computer with Spybot, Ad-ware SE and Panda yesterday and deleted all of the infected files that I found.
Also, I cleaned all the stuff up by the ATF-Cleaner.
My Windows and Symantec are both updated.
So what have I missed or done wrong?
Is my computer still being infected?
Pls help.........

Are you referring to Spybot alerts on Windows Security Center as discussed here and here?

I'm not quite sure..........
In fact, I am a computer idiot..........
So I dun really understand much (may be 40-50%......) about the pages u posted............
Is it telling me that Spybot is crashing with my Windows Security instead of my computer was being infected.........???

The discussion is telling you that Spybot flags certain Windows Security Center registry changes as risks. This alert is informational to bring to your attention that "someone" disabled one or more notifications in the Windows Security Center. Without knowing exactly what alerts you are getting I am using "Windows Security Alerts" which you posted in the title of your thread to see if this is what your talking about.

This could be an entirely different alert but I'm trying to pinpoint where the alerts are coming from and exactly what they say.

o..........
thx anyway first!!!

there is an icon shown up at the right-bottom corner of window
and telling me "ur comupter may be at risk...." sth like that.
Then i open it and it show that "Symantec AntiVirus reports that it is installed, but its status is unknown."
that's all i know........
does these information help?

OK that makes more sense. Does it look like Fig 01 here?

Fig 1
exactly!!!

but it shows "Symantec AntiVirus reports that it is installed, but its status is unknown." in stead of "Window s did not find antivirus..........and other security threats." in Fig 2
and my Automatic Updates is "on" but not "check settings"
just like the firewall

See "Manage Your Computer's Security Settings" and "FAQs about Windows Security Center. If your anti-virus is Norton, then also read here.

there's no more symantec update is available already
i've made it to be most up to date yesterday
windows also
but the alert is still...........