I have installed IE9 and IDM integration no longer works. How to fix this?
When you install Internet Explorer 9, it offers to disable add-ons to speed up the browser. Probably you accepted this offer. Now you need to enable IDM add-on back.
Please use "Tools→Manage Add-ons" ("Tools→Manage Add-ons→Enable or Disable Add-ons" for older versions) Internet Explorer main menu item.
Then find "IDM integration (IDMIEHlprObj Class)" add-on (arrow 1 on the image) and enable it (arrow 2 on the image).
If the problem will repeat then some program keeps blocking IDM add-on. It can be some kind of security program: FireWall, Antivirus, SpyWare/AddWare Remover. You need to locate this program and change its settings or uninstall it.