When i right click on any drive icon.
You are right, right clicking on a drive icon and selecting the "Scan using Spybot Search & distroy" causes the spybot list area to flicker and appears to not be work but when right clicking on a single file it works just fine.
It would seem to me that either the install should be smart enough to not put the context option on a drive icon menu or make the feature work for an entire drive as well.
Just to be clear,
1. Spybot works by scanning a system drive only - right?
2. Does it scan the entire drive or do you have to scan each user account?