cannot install newest version of itunes

+So i recieved my comp back after the second motherboard replace (we won't get into that one),+

That sounds like the noir household nightmare with our Gateway Vista box (we had to swap out/reinsert virtually everything else but the motherboard).

+An error occurred during the installation of assembly ‘Microsoft.VC80.CRT,publicKeyToked=”1fc8b3b9a1e1833b”,type=”win32”,version8.0.5 0727.762”,processorArchitecture=”x86’”.Please refer to Help and Support for more information. HRESULT:0x80073712+

Let's try getting an installer log to the Apple Engineers with that one.

1. Open a command prompt window. (Start menu > All Programs > Accessories > Command Prompt.)
2. Drag and drop iTunesSetup.exe onto the window so that the full pathname of the file is at the command line prompt.
3. Type in a space, then the following line:

/l*v C:\log.txt

4. Hit return.
5. The installer will create a log file:

C:\log.txt

Find that file and send it as an attachment to this email address: royb@apple.com

in the email to Roy, be sure to include the following information:

- A link to the thread on Apple Discussions where the issue is being discussed
- The username you are using in the thread
- The version of iTunes you are using or trying to use
- the version of Windows you are using (mention service packs or specific flavor of Vista)
- A concise description of the issue you are seeing
- The exact text of the error message you are seeing

I'm not sure if you still need help but I was getting the same error until 10 minutes ago. I decided to uncheck "set as default audio player" and was able to install just fine this way.