Please uninstall Norton AntiVirus 2004 now because:
1. Your Norton AntiVirus 2004 's database is outdated and therefore cannot protect you against latest threats.
2. Turning on the real-time protection of more than one antivirus at the same time would cause conflicts and slow down or even crash your computer ( as you are now experiencing )
3. Antivir's protection is efficient
Note: Antivir Personal Classic ( i.e. Free Version ) cannot detect Ad/spyware,
so I recommend you to install AVG Antispyware, Spybot S&D, Adware to clean up the ad/spyware
The download links of above programs are available in my website at the bottom of this answer.
For your Question:
"if detect 到virus 要del,係唔係整個file del"
You mean 檔案? Ans: Yes.
To remove the trojan detected bt antivir, please update your Antivir, enter Safe Mode :
http://www.pchell.com/support/safemode.shtml
and do a scan to try to remove the virus.
OR
Use killbox or filseclab power removal
KILLBOX:
Download:
http://www.softpedia.com/get/Security/Secure-cleaning/Pocket-Killbox.shtml
User Guide:
http://killbox.net/help.html
Filseclab power removal
http://www.filseclab.com/cht/tech/trojan-horse.htm
If above method fails, please go to Antivir's Forum and ask for help:
http://forum.antivir.de [ free registration required ]
For more information about PC security, please visit my website:
http://removevirus.blogspot.com