Ever mispelled a web site name, and get taken to a different one that
then downloads some adware on your pc?  That's what happened to my
friend.  How can he find the program that is running and disable it? 
He's running XP Professional.

Hi blue_bna,

Here is an excellent website which explains what spyware/adware is,
what to do if you have it, and how to prevent it from happening again.
Make sure you update any software after you download it before you use
it.

Dealing with Unwanted Spyware and Parasites:
"What is Spyware? A technology that assists in gathering information
about a person or organization without their knowledge. On the
Internet, "spyware is programming that is put in someone's computer to
secretly gather information about the user and relay it to advertisers
or other interested parties." In some cases even after these programs
have been removed from your system. As such, spyware and or Malware is
cause for public concern about privacy on the Internet. These type
applications also in many cases can cause unknown browser problems."

How To: Safely removing these Parasites from your system:

1) Ad-Aware: 
http://www.lavasoftusa.com/support/download/
Forum: http://www.lavasoftsupport.com/

2) SpyBot: 
http://beam.to/spybotsd
How To: http://www.tomcoyote.org/SPYBOT/
Forum: http://www.net-integration.net/cgi-bin/forums/ikonboard.cgi

After using one of the above, download HijackThis to make sure you
found everything:
HijackThis:
http://www.spywareinfo.com/~merijn/downloads.html
Tutorial:
http://www.spywareinfo.com/~merijn/htlogtutorial.html

Dealing with Unwanted Spyware and Parasites: HijackThis:
"Editors Note: Since HijackThis does not (yet) come with a install
routine, create a folder via Windows Explorer for HijackThis, then
move the zip file to this folder. This way any backups created are
saved in a legit folder. I've seen too many instances where the user
runs HijackThis from a temp folder and any backups are lost if that
temp folder is cleaned out. You should also make sure you are using
the latest version each and every time you run HijackThis, as there
are new detection added all the time.
- Unzip, double-click "HijackThis.exe" and Press "Scan".
- When the scan is finished, the "Scan" button will change into a
"Save   Log" button.
- Click: "Save Log" (generates: "hijackthis.log") HijackThis Tutorial
(recommended read)
- Next, go to: http://www.spywareinfo.com/forums/
- Sign in, go to the "Spyware and Hijackware Removal" section.
- Press "New Topic", copy and paste hijackthis.log into your new message.
Visiting the SpywareInfo Forum or one of the other recommended Forums,
to finish cleaning up your system is highly recommended. As neither
Ad-Aware or SpyBot can no longer completely remove these pests. This
is mainly due to new daily threats and the use of random generated
filenames used by these parasites!"
http://mvps.org/winhelp2002/unwanted.htm

Additional Links:

Webopedia: Spyware:
http://www.webopedia.com/TERM/s/spyware.html

CWShredder:
http://www.spywareinfo.com/~merijn/files/CWShredder.exe

MajorGeeks: Spyware Links:
http://www.majorgeeks.com/downloads31.html

Spychecker: 25 Top Downloads:
http://www.spychecker.com/topdownloads.html

I hope this helps your friend. If you have any questions, please post
a clarification request before closing/rating my answer.

Thank you,
hummer

Thanks for the great information.  It's very helpful.  By the way, how
long do these quesitons and answers stay posted?

Thank you, blue_bna, for your nice note, rating, tip - all is
appreciated. As far as I know, questions/answers will reside here as
long as GA is here - at any rate, they haven't removed any yet.
Sincerely, hummer