Downloaded program installed second "Explorer"

From: Wimpyjoe (bradley_marx@hotmail.com)
Date: 05/31/02 

From: "Wimpyjoe" <bradley_marx@hotmail.com>
Date: Thu, 30 May 2002 18:35:03 -0700

Hi! One of my sons allowed a program to download and
install a new "explorer" that loads when I start the
computer - I now have 2 explorers running at once. The
new one keeps accessing the Internet and showing Casino
sites - a new window opens like every 15 seconds and
overwhelms the computer. Can someone help? I can not
find the offensive file on the machine.