that was my best guess, based on the symptoms (most of the sites you
listed are either search engines primarily or offer web search
capability as a feature). If it were me, I still would try at least the
following: HiJack This (specializing in hijackers), CWShredder
(specializing in a particularly stubborn hijacker), Microsoft's free
anti-spyware detection/removal tool, and the 15-day trial version of
CounterSpy.
Don't think that one anti-spyware product will detect all known
infections. Even the best anti-spyware product detected less than 67%
of all spyware infections placed on a test computer by a testing lab,
according to the last article I read on the subject.
Also read the section titled Leak Test at
www.grc.com.
You will be amazed how easy it is (on the great majority of
insufficiently configured PCs) for any evil program to rename itself to
explore.exe (after renaming the real explore program to something else),
and then start using default permissions already granted on the cheap
hardware router or pseudo-security suite (e.g. port 80 or port 110) to
start sending all your personal data to Russia.
Which leads to my last suggestion. Delete or rename your explore.exe
and replace it with one from work. Compare the version, date and size.
If different, maybe you have an infection masquerading as explore.exe.
Of course, this suggestion is only valid if your work PCs are not
using an infection masquerading as explore.exe too.