Question about running Adware/Spyware detection software on an XP machine with more than one user account.

[ddeder]

I have a computer running Windows XP Home with several user accounts set up. This machine became heavily infected with adware and spyware. When I run Adaware, Spybot Search & Destroy, PestPatrol, etc... all kinds of adware/spyware files and registry entries are identified. I have the program remove these problems. I then sign on under a different user ID and run the software again from there. A zillion more problems are found and have to be removed... I have to do this for each user ID. It seems to me that with Anti-virus software, scans do not have to be run for each user account, correct? Is there a way to run the adware/spyware scans so that they only have to be run once?