Are you running XP or Vista or Win 7??? If you're running XP you can't use IE9. That's your problem. IE9 is only for Vista and 7. In addition, you need to make double sure that you have every single file from IE deleted from your computer when you uninstall it. This means from the registry, too. Have you been doing that? If not then that is why you've had to re-install IE so many times. Leftover files can sometimes confuse a program when it's re-installed.
1. Uninstall IE by the method you've previously used.
2. Use the Search feature of Windows to find and delete any leftover files that IE may have left.
3. Backup and then clean the registry of all entries there that IE has left. Make double sure that you do NOT delete any entry that you're not absolutely positive is something for IE. If you delete the wrong entry you will ruin whatever software that entry goes to. This includes your operating system.
4. From your previously saved IE .exe (installation) file re-install IE while booted into Safe Mode without Networking.
5. Once IE is installed, Defrag while still in Safe Mode without Networking.
6. Re-boot into Regular Mode.
This should do the trick for you.