I took your subject as the Google which is: http://www.google.com/search?q=Control%2FEnter+shortcut+in+IE+broke
Just 7 itmes down I read http://forums.techguy.org/showthread.php?t=117534 and they noted "OKAY......I have finally fixed this problem on my own. I was looking in internet options under the content tab. When you click the autocomplete button you will see a choice for address, as long as that is marked, you can use the "control/enter" shortcut to enter the address when it is a "www dot com"."
The Control/Enter shortcut in IE to add the http:// and .com (which I use constantly) suddenly stopped working. I don't know what changed, and I ran three different virus/spyware scans, all of which came up with nothing. I run XP/SP2 with IE6. Thanks for the help!