I've got a similar problem....
A while back I had an ATI card and radlinkerinstalled. I uninstalled the ati drivers, installed an nvidia card, and radlinkerwas still there. I uninstalled it, but its tab remained in display properties, albeit empty. All seemed acceptable...
That is until I installed windows xp pro over home. As it was installing, for whatever reason it decided that radlinker was a critical part of the OS. Unfortunately, I no longer had the install files, nor where they available on the Internet due to it being an older version. This caused it to bring up an "Installing radlinker" dialog whenever I ran ANY program. Eventually I went into the registry and deleted all references to radlinker .....which got rid of the prompting for a file location and reference to radlinker, however whenever I run any exe file the "Installing..." dialog box still pops up momentarily, and then disappears.
Pretty damn annoying and makes everything take longer to run, especially boot up. Any ideas how to kill it?
BTW, the exact box that pops up is says "Windows Installer: Preparing to Install."