I do not know what did I do. Until two days ago, I could type in the URL in the Start-Run field and that was enough to take me to the webpage. Now I get the message:

"There was a problem sending the command to the program"

and the browser opens blank page with nothing in the address field. The same message shows up for any URL whether it begins with http or with www. If I type in the name of a file on my disk, the file runs normally, only URL do not run. Virus checked, negative. The URL runs well if it is entered in the address field of the browser (IE6 and all updates installed)

Any hint?