visual C++ 2008 update problems

I'm on win7 Ultimate 64bit & i have developed a problem. I cant install the win7 visual C++ 2008 update SP1 as i get Error code:643 every time.

This also prevents me from installing nero as that also tries to install a version of win7 visual C++ 2008 & gives an error at that stage & then closes itself.

I've googled about & some suggested a reinstall of my OS which is not an option as i would lose to much.

Really need help on this as im out of options of what to do

Thanks

Edit...

Update on things.. Ive gone into cpanel n uninstalled all the Visual C++ files which i only had 2008 redist sp1. I continue to try install 2005 version & i get this error..

Error 1935. An error occurred during the installation assembly.
"Microsoft.VC80.ATL.type="win32".version="8.0.50727.762".publicKeyToken="lfc8b3b9a1e18e3b".processor/Architecture="amd64"".
Please refer to help and support for more information.

I tried the registry option found on google but i dont have those entries shown.