I have a brand new Dell, using Windows XP.  When one user is logged on and has the internet open, and then a second user attempts to get on-line, the second user always gets the following message: "Program: C:\Program Files\internet explorer\iexplore.exe" and the second user is prevented from getting on line.  I get a similar message when one user has the internet open and the other user attempts to open the Control Panel: "Program: C:\Windows\explorer.exe". I am quite incompetent when understanding all the issues involved with computers.