Well it looks like Loren's problem is different than yours. She wants to do forensics on a comptuer to determine what sites this person is going to in order to scan for offensive sites that install spyware. You just want to get it stopped.
I will address both issues and if you dont mind posting a reply at the other site with a link to here with the info that would be great
For Loren's issue, if they have access to the machine and they use Internet Explorer, there is an excellent tool to dig around in a history file used by IE. This file is called the index.dat file.
The tool you would use is found here:http://www.foundstone.com/resources/proddesc/pasco.htm
When a person visits a site with IE, IE updates the following files (This assumes XP. Search for index.dat if using other oses):
This is the history file. If a user wipes their History in Internet Options this will be empty.C:\Documents and Settings\\Local Settings\History\History.IE5\index.dat
IE uses something called temporary internet files that supposedly makes web browsing quicker by loading some of the content locally from stored material on your machine. Everytime it downloads something, whether that is an image, a file, or video, it records it in the index.dat here. Once again if they clear the temp int files, this will be empty.C:\Documents and Settings\\Local Settings\Temporary Internet Files\Content.IE5\index.dat
Simply download the program and extract it to the C: drive. Then go to the directory where the index dat is, for example:
C:\documents and settings\\cookies\
and type c:\pasco\bin\pasco index.dat > cookies.txt
Then open excel and open the cookies.txt file with excel. Just press finish when it asks you about importing the text. Now you can sort through the various data.
If you do not have access to the machine, you can use a sniffer like Ethereal if you are on a hubbed network and not a switched network. If that wont work for you, use a keylogger or other tracking program. Just google for one. Lastly, and the most expensive, would be a proxy server.
For most of your needs the pasco tool should be more than enough.
For your spyware issues I always give people these tips on keeping their machine clean. If you have a specific problem, feel free on letting us know. GO to this link for the preventative tips:
How did I get infected and how do I prevent it from happening again?
Hope this helps and was the info you were looking for