Can I Remove Individual SPs?

I noticed in my Windows "Add or Remove Programs" window, that 3 versions of SW 2009 are listed - SP0, SP4 & SP4.1.  The are approximately 2600 MB, 1800 MB & 1600 MB, respectively.  Can or should I remove the previous SPs?  I was surprised to that there was not just one current version listed.SolidworksAdministration