You can try searching your system for them. If found you can use properties to check the date and time of installation. Then do another search for files etc installed or created on that same date. Might reveal something.
I have searched for them on my computer (but not registry as of yet). I haven't got any spyware (recommend any?) and I have Norton AV 2003 with all virus defenitions updated. Ran a full system scan today with no infected files found