I've always used
PC Decrapifier on a new PC to remove all the bloatware. You don't always get clean install disks with new computers, so this is the next best thing.
Indeed

I don't have win7 disks, as the pc came pre-installed with it (a typical run-of-the-mill store-bought package-deal

)
It does work well though. Except of course for this strange mix-up with BIAB and Sony PC-companion.
Thanks for all suggestions in this thread

It's a puzzle, but I'll just live with it as it is for now.