Hi archmedes,
First of all a Quick Scan is run whenever a new virus def is downlaoded and the system goes into Idle - in other words - while you are not doing anything, so perhaps it is something else that is bogging down your systems - perhpas something like not completely removing another AV program prior to you installing Norton Security Suite.
Also, what you are calling garbage can be turned off and those tasks do not have to be run as part of the program.
You mentiond new version - could you tell us which version you had before and which version you have now? How long it has been since you installed NSS and how you installed it - did you remove any other AV prior to installing it? You can find the version number from the main [page of NSS by selecting Support > About.
Perhaps if you tell us specifiaccly more about your operating system, how and when you installed NSS, exactly waht you are tryng to stop and how you can tell that it is the Quick Scan that contiues to use your resources we can help you.