Norton doesn't do the job well i think

I just scan a USB flash disk with a virus... Norton 2009 (with latest definitions) does remove it but the consequences are, the virus (W32.SillyFDC will damage 50registry keys) destroyes my registry keys thus disabling my system tools, on/off system restore, defrag, computer managment, regedit etc... this is not good. i just wish that norton removes the virus before the damage is done not after. because i already reformated my computer a couple of times because of this.

 

How will i scan some files such as within a USB flash disk or other Hard disk without destroying my system?