Seems I'm not the first to say this...
...but +1 for Secunia PSI! Although it doesn't avoid having to reboot it does a reasonable job of automatically identifying obselete applications and managing their updating on Windows PCs for personal use (I believe there are non-free corporate suitable versions too) so that likely everytime you DO reboot something gets updated. It has become the first thing I install on anyone's "...it seems a bit slow and it's asking me to do things, would you mind having a look at it?" computer. You can also set it up to update everything and keep out of the way. This generally significantly reduces the frequency of this question being asked.