I just installed Solidworks 2015 SP0 from DVD. When the Background Downloader informed me that SP2.0 was available I (mistakenly) chose the option to download the service pack to my computer instead of automatically installing it. When I go to the folder where the SW2015 SP2.0 is located, there is no executable installion file to install the service pack. Now, if I go back to the "Check for Updates", in hopes of going back to an automatic installation, I get error messages and can not download or install the service pack. I am starting to realize that full automatic mode works best for any Solidworks updates, but I would like to get around this problem without doing a full system restore.
Problem solved. I had a brand new hard drive from Dell that apparently had a corrupt operating system. A complete reformat and new windows OS did the trick. Everything works as it should now.