For all of you out there working on Software Factories or just automating Visual Studio using GAX/GAT we've put up a small tool named GAX Troubleshooter (yes, we didn't spend much time on naming it).
Upgrading versions of GAX, installing and uninstalling guidance packages has been usually a bit of pain (ok, a lot of pain in several cases), if you add a new version of Visual Studio to the picture (yes, VS 2008), this may confuse things even more.
Usually, if you properly install GAX and then any guidance package and then you uninstall any of them before uninstalling GAX itself, you're safe.
But... (and yes, there is always a but) people often delete guidance packages before uninstalling them which then forces you to play manual tricks in order to make GAX happy to uninstall.
Is for this later case that we put up this little tool: it will report key registry entries, files, etc regarding to GAX. And with this information it should be much easier to diagnose what may be causing a failed installation or un-installation.
You can download the tool from here, and this is the place to post the generated log file if you want to get help making sense out of it.