I'm not sure I understand you. You did remove SiteAdvisor using Control panel/Add or Remove, or you didn't?
It sounds like you should try removing it completely that way and reinstall it if you want to use it.
It is listed either as McAfee Siteadvisor or McAfee Security Center if other McAfee products are present and if the latter then you choose which part to remove.
If that doesn't help then I would use the MCPR removal tool linked in my signature which will remove all trace of McAfee products. Then reinstall from your account or http://www.siteadvisor.com