When I had to rebuild my Sony from the restore partition, I found out that the bloat is installed in a second step. First the os drivers and such installs in a pretty standard MS way.

Then there is a second reboot, where all the bloat is loaded. If you kill the installer, you end with a cleanly installed system that runs quite fast.

The problem I had was that I didn't know how the track down method by which the second boot bloat install was being called - as the next boot would start the install again.

Edit: btw, If you are no fan of NAV. Trying to uninstall it is a pain. Symantec provides, on their website, a special uninstaller that really does the job.