Well, this happened to me, after I uninstalled some program. Internet Explorer 64-bit would open, but IE 32-bit would just not open on my Windows 7 64-bit. Nor would Internet Explorer No Add-ons open. When I clicked on the icons of these two nothing would happen; but when I clicked on the IE 64-bit icon, it would spring to life.

I might not have noticed it, since I have the IE 64-bit icon pinned to my taskbar, but when I tried to click the links on my Twitter clients, the default browser, which is the Internet Explorer 32-bit, would not open. Nor did any links open when I clicked on them in my default mail client, Windows Live Mail. I would get the message:

This file does not have a program associated with it for performing this action. Please install a program, or if one is already installed, create an association in the Default Programs control panel.

I navigated to Control Panel\All Control Panel Items\Default Programs and opened Set Default Programs. I found that Internet Explorer was missing here!

If you too face this problem, you might want to try some of these troubleshooting steps.

1. Open Set Program Access and Computer Defaults and set Internet Explorer as the default web browser.

Now see if the Internet Explorer entry appear in the Default Programs box. If it does, click on Set this program as default and Choose all the defaults for IE. If it doesnt work for you try the next suggestion/s.

2. Run System File Checker. Restart and after a reboot see if IE 32-bit opens.

3. Re-register the concerned dll and ocx files and see if it helps. You may use Fix IE or IE Restorator.

4. Run system restore and restore back to a previous good point. You might want to try running system restore in safe mode, if the regular one does not work properly.

5. Quickly back up your IE favorites and other settings using FavBackup or MailBrowserBackup and then Reset Internet Explorer Settings.

5. Uninstall and then Reinstall Internet Explorer. You have to uncheck the box and click on OK to do it.

I am sure one of these suggestions will help you. Once you have solved the problem, you might wat to visit Defaults Programs and confirm that IE is indeed visible and Set Internet Explorer as default and Choose all the defaults for IE.

Hope something here helps you!