Recently this virus had effected my girl friend's computer. The symptoms it gived are slowing down the running process, force on 'do not show hidden files and folders' in the folder option, cause Norton files crashed and cannot be updated and used further, cannot run Microsoft Office.
I roughly know the virus is Trojan Pws and its name may be Trojan PWS.QQ Pass with Norton's virus definition. I know it had altered the registry values so that everytime I cannot switch to 'show hidden files and folders'. I had check the HKCU\software\microsoft\windows\currentversion\pol cies\system\run
but it seems clean, so that's for same place of HKLM. I'm headache now...Please help me anybody...

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Norton is more then capable of crashing by itself

What I would suggest you do is install Avast! Home Edition and schedule a boot time scan. Then you should remove your user account from the administrator's group.

I finally cure it. By change the setting in registry in the following address
HKLM\Software\Microsoft\WINDOWS\CurrentVersion\Exp lorer\Advanced\Hidden\SHOWALL
I deleted the value of CheckedValue by type of REG_SZ, and create a new value of CheckedValue by the type of REG_DWORD and with the value of 1.
And then I switch to 'show hidden files and folders' and 'show system files and folders', by the way I know the virus files, which are:
C:\WINDOWS\system32\SVOHOST.exe
C:\WINDOWS\system32\winscok.dll
sxs.exe and a autorun.inf files in every drives.

megamanced,
Improper using of Norton may crashed the system. What I mean by improper use is block few of its features such as its Internet Worm Protection instead of Windows Fire Wall. Norton is good as I what I had expected since the first time I chose it, from its features of few protections against spyware, adware, virus and malicious. I do prefer to the anti virus that have the detail of the virus data in their company site. The anti virus such as Avast is lack of the features and informations. Meanwhile Symantec and TrendMicro do have.
Anyway, my problem is not relavant with what anti virus I suppose to use. Most of the viruses I fixed and terminated not by anti virus, but directly search its files and permanently delete them. Once a pc infected, anti virus is hard to react and take action. So I want to convey is prevention is better than termination.

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This is absolutely true

Although Norton is usually the first AV to fail post-infection, due to the fact that widespread popularity means it's a common target for AV-disabling viruses; if kept properly updated, Norton is one of the best at preventing infections occurring.

Thanks syphus. Recently I did XP-No-Reformat on my pc, I believethe process did change the registry value and deleted the Norton's subscription period. So now I had changed the anti virus to Avast! Home Addition v4.7.

Base on the few views from other site, we are recommended to install a extra Fire Wall. I know Norton has Fire Wall itself, which is Internet Worm Protection if I didn't wrong. So I wonder what's sphus's opinion against my case.

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