InstallAware

I have a question concering Upgrading. Once I have asked you about patch, but I didn't use it for upgrading for the following reasons:
1) During Upgrading I need to create new IIS site, but the original installer does not create/delete the site, Therefore; there is no way to delete the site on uninstallation
2) It is not possible - when I move installed files around. In this case I'm technically breaking the installed state of the product.

Therefore, I created a totally new project as a upgrading and I called it "upgrade". During the installation of upgrade I did the following:
1) Deleting Uninstall-Directory of the previous version.
2) Deleting shortcuts from startmenu and startup directories of previous version and creating a totally new shortcuts instead.
3) Deleting IIS site, which has been creating by previous version and creating two sites instead.

But during un-install of upgrade I tried to uninstall both itself (i.e. upgrade) and previous version (i.e. uninstalling previous version manually by deleting directories and files, moreover deleting keys inside registry that might points to previous version). But unfortunately I couldn't success to manage that, because once I try to install previous version again, I found that the installer can detect something and then it will forward installer to go through uninstall first before start installing. Moreover, I run File Monitor and Registry Moniter through installation and uninstallation in order to see where in the registry or files installAware read from in order to check whether there is a previous version of installer.

For all the previous description, I would like to get some help if I would like to uninstall previous version manually,

Looking forward to your response,

Thanks in advance,

All of the custom things that you wish to do can be done in the script. But you have to let the standard auto-uninstall procedure complete first, because that is the only way Windows Installer will deregister the installed old version. This is why the old version is still being detected and you should let the regular uninstall complete - tampering with Windows Installer's internal data stores will be very risky and extremely unreliable as they are not documented and may vary from platform to platform.

After the auto-uninstall completes, you may use the script to also remove the IIS sites that you had created (as these will not have been removed), and also execute any other tasks in the script - just add your scripting commands normally right after the block that executes the uninstall in the pre-reqs section of your setup.