how do i re download bonjour without re downloading itunes

Uninstalling and then reinstalling your iTunes should also get your Bonjour reinstalled.

For the reinstall, use an installer downloaded from the Apple website:

http://www.apple.com/itunes/download/

... or you could get it back via your Apple Software Update for Windows.

If you'd prefer not to uninstall iTunes, try the following procedure.

Download and save a copy of the iTunesSetup.exe (or iTunes64setup.exe) installer file to your hard drive:

http://www.apple.com/itunes/download/

Download and install the free trial version of WinRAR:

http://www.rarlab.com/

Right-click the iTunesSetup.exe (or iTunes64setup.exe), and select "Extract to iTunesSetup" (or "Extract to iTunes64Setup"). WinRAR will expand the contents of the file into a folder called "iTunesSetup" (or "iTunes64Setup").

Go into the folder and doubleclick the Bonjour.msi (or Bonjour64.msi) to do a standalone Bonjour install.

Here is a direct link off the Apple site as well for everything Bonjour. It has links to all the downloads.

https://www.apple.com/support/bonjour/