Installers not working on VISTA

I am getting an error when I try to install Quickbooks 2007, or uninstall
Quickbooks 2006, or install the smartupdater for my IBM laptop, or run a
patch for my Quickbooks 2006. I also get this error when I try and run SP1
for .net 1.1. The error I get is:
Error 1618 or 1500
Another installation is in progress. You must complete that installation
before continuing this one.

I figured out along the way that I don’t need SP1 for .net 1.1 because VISTA
has 2.0 installed. However Quickbooks doesn’t get it and tries to install the
SP.

I have run these programs as administrator, I have restarted to ensure that
there is nothing else running, I even got some smart girl from Intuit on the
line who had me create a new user account, add it to the admin group and then
disable all startup items in msconfig. Worse yet, I followed her bad advice
and ended up locked out of my computer for a day because my VISTA
installation decided that it needed activated again and was not a genuine
copy of Windows. It wouldn’t take my PID and the call in activation didn’t
work either. Don't try this at home folks. Vista apparently needs something
in the startup group for it to validate itself.

Any advice would be greatly appreciated!
--
ms