Try to download NSS and SCAN..
ftp://ftp.symantec.com/misc/tools/nss/
How to run the Norton Security Scan on a machine with limited or no internet connectivity.
1. On a machine with network connection, follow Step 1. and 2. and extract the files to C:\VirusScan\NSS and launch NSS.exe.
The Virus definitions will download to the local machine here: C:\Program Files\Common Files\Symantec Shared\SymcData\virusdefs-2.5-e\<date.rev>).
2. In the C:\VirusScan\NSS folder, create a folder called “VirusDef” (example C:\VirusScan\NSS\VirusDef)
3. Copy all the virus definition folder content from \<date.rev> folder (example:20080725.003) into the VirusDef folder
4. Copy the entire VirusScan folder to a thumb drive.
5. Now you can start NSS.exe from the thumb drive. It may complain about definition might not be the latest, but you can skip that message.
I have not checked NSS in safe mode... after doing above procedure try in safe mode.....