Could it be you got a virus?
Try Spybot S&D, and Adaware
To the two or three other Sansa users out there:
I updated my Sansa firmware (makes the player much better) and my computer seemed fine. The next morning, it was so messed up that I couldn't even boot up in safe mode. Chkdsk repaired some things on the C drive and it seems to be better again.
It was probably just a coincidence, but I was wondering if anyone else had a similar problem.

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