If you're comfortable editing the Windows registry, here's how you do it:
Close all open browsers.
Using the startup menu's Run... menu item, run regedit.exe.
Navigate to the following section of the registry:
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\TypedURLs
On the right, you'll find a series of entries named url1, url2, and so
forth. Find the one you want to delete and right-click on the name. Select
Delete and confirm the deletion.
The next time you bring up internet explorer, the dropdown list in the
address bar will now include only the URL's with lower numbers, since IE
stops processing the list when it finds a gap in the numbers. To keep the
higher-numbered ones, rename the highest-numbered entry to the same name as
the one you deleted. You do that by right-clicking on the highest-numbered
entry name, selecting Rename, and renaming it to the name of the one you
deleted.
If you need to do this frequently, you can save the typedURLs location in
regedit's Favorites menu, and then go directly to that section by selecting
it from Favorites.
HTH,
Tom Dacon
Dacon Software Consulting