i had a toolbar hijacker on my computer recently, i ran xoftspy, spybot search and destroy, adaware, plus a load of other anti spyware/virus type programs but they couldnt get rid of it. i ended up reinstalling xp and starting again.
ive used mozilla firefox in the past, but it is really really slow. it takes forever to load pages, and it just gives up most of the time.
the best browser ive found is avant browser, its loads more secure than internet explorer, and loads faster than mozilla firefox.