Remove Nmain.exe from systemdoctor

Need help to remove..'Dmain.exe'

I am still running WinXP SP3, I have Norton Security Suite but also a symantic pro systemworks for systemdoctor/windows doctor that I used for years for the maintance programs only. now systemdoctor will not open or work as it's desktop icon shortcut target address has changed/hijacked to read "C:\Program Files\Common Files\Symantec Shared\Nmain.exe"  a search of Symantec has said also known as Klez worm and I ran the Norton fixKlez tool but it found nothing, I uninstalled the systemworks many times and reinstalled, ran registry cleaners in between and it's still there... Is this a worm I need to worry about? nothing seems to find it yet it blocks systemworks systemdoctor... have used Norton Power Eraise and Norton Removal Tool

 

Thank You for any help