Norton / symantec, Id still recommend differant antivirus
Yes the built in firewall and your router are sufficient
Download "Suspicious File Packer" Third one on this page >
http://www.safer-networking.org/en/tools/index.html
To your desktop, unzip the file inside
run sfp.exe copy then paste the list below into it and hit continue.
C:\WINDOWS\system32\wnstssv32.exe
a .cab file will have been created on your desktop
attach it here Please.
http://www.thespykiller.co.uk/index.php?board=1.0