Can't upgrade from OS 10.9.2 to 10.9.5

Hi all. I'm running OS X 10.9.2 and I'm trying to upgrade to 10.9.5. Software Update says that it installed 10.9.5 today but when I go to About This Mac, it still says 10.9.2. I then downloaded the 10.9.5 OS X Update file and it won't let me install on my Macintosh HD. The installer says, "OS X Update can't be installed on this disk. This volume does not meet the requirements for this update." I ran Disk Utility and the disk checks out fine. I tried changing the partition size as was suggested in one bulletin but that did not help. I have backed up the HD. Any suggestions?