This may go without saying these days, and I am no expert, but it sounds to
me like you are the victim of a virus or spyware of some sort. Are you
running up to date virus protection? Have you scanned your system with any
spyware? I have seen similar results with some of the machines here in my
office. Get a copy of Adaware, Spybot, or other similar scanning software
and see what comes up.

--
Thanks,

Jeff
90' Carat (It's Blue, It's Beautiful, It needs a lot of work)
86' (Soon to be donating organs to the 90')
85' GL (sidelined but to be resurrected in the near future)