Rootkit.Boot.SST.b is NOT coming off! PLEASE help

My laptop won't boot to windows and sits at a cursor just as soon as I turn it on.  I took off the hard disk and scanned it on another machine as a secondary drive and the ( Rootkit.Boot.SST.b ) came up and no antivirus program can't delete it, cure it or quaranteen it! Please help on how to get it taken off.  I have read many forums and still no luck.  Seems no one knows how so that is why I cam to Norton as Symantec has been the best one I've ever found and has worked for me.  Thanks, Chepo