Windows ME is a waste of time ("it blows man"). I would suggest upgrading to XP.
(“They say if you play a Windows ME disc backwards, it tells you Satanic messages.
Worse, if you play it forwards, it installs ME.”)
No, being serious, I would suggest turning off system restore in ME. Then boot to safe mode, and re-run the virus scan.
Now go back into normal Windows, and run Spybot
(only turn System Restore back on afterwards).
Also, it may help to run Spybot at system startup, rather than when windows is running.
Also, re-install NIS. Take out all registry values in HKLM and HKCU that have anything to do with Norton or Symantec before you do this however (remember to backup your registry first).