Woo Hoo! That was it! Thank you so much for rooting out the problem.
BTW: The developers of Speed Download know they need to make an automatic uninstaller, but haven't yet. Instead, they posted these instructions for manual removal deep in the bowels of their website:
http://www.abtdata.com/english/software/sd/support.html
Manually uninstalling Speed Download:
There is an automated uninstaller under development. In the meantime, if you would like to uninstall Speed Download from your computer, here are some easy to follow these instructions:
Under Classic: Drag the following to the Trash:
- The Speed Download folder
- Speed Download CMM (found in: System Folder/Contextual Menus)
- Speed Download Browser Plugin (found in: System Folder/Internet Plug-Ins)
- Speed Download Preferences (found in: System Folder/Preferences)
Under MacOS X: Drag the following to the Trash:
- The Speed Download folder
- Speed Download Browser Plugin (found in: User/Library/Internet Plug-Ins)
- Speed Download Preferences (found in: User/Library/Preferences)
- Open your browser's preferences, and go into the 'File Helpers' section.
- Delete all entries that contain Speed Download.
- Quit and restart your browser.