home address changes

From: Rob (rob@swc-wistex.com)
Date: 12/20/02 

From: "Rob" <rob@swc-wistex.com>
Date: Fri, 20 Dec 2002 14:25:03 -0800

Here is my problem.

I logged on my internet connection and started Microsoft
Internet Explorer, when this munky.com appeared as my
default address. I check the home address and sure enough
this munky.com was now set as my default home address.

How can this happen, with this new site saved as my
default setting? I am sure no one was using my system
since the last time I did.

So, my question is how do they get their site saved on my
system and how to eliminate this from happening again.

Thanks for any input.