Downloader.MSCache

I like Norton, as it seems to catch things just fine, but I'm never sure from their instructions what I'm supposed to do when something gets caught. Tonight, I re-upped with Norton for the next year, downloaded the latest definitions, and ran a full scan. It said I had a virus, Downloader.MSCache. The file name was randomiser.exe and the path was C:\WINNT\system32. Norton said it couldn't be repaired and quarantined it. I did the submit to Symantec thing and received instructions as follows.
1. Disable System Restore
2. Update virus definitions
3. Disconnect from the internet
4. Unregister the browser helper object
5. Restart in Safe mode
6. Scan for and delete the infected files
I wasn't sure of the full path and file name of the infected .dll, so I followed their suggestion and did another full scan to learn this, but this scan came up empty.
So, do I need to do anything else, like the above instructions, or am I fine as is?

 

Actually, I never did steps one through six. I did another scan so I could write down the full path and file name of the infected .dll prior to beginning following their instructions. That scan came up empty so I wasn't sure if my computer was no longer infected or what. I am also not sure if that file is now deleted and if it is something I need. If it is something I need, I don't know where I would go to replace it.
Obviously, there is a lot I don't know!