Go to Start>Run? type msconfig and hit Enter. See if you can see an entry relating to pcts Tray Entry point not found and if so untick it. While you are there look at all the boxes which are ticked and untick any not needed click Apply and reboot.
Then download and run CCleaner click here and see if there is any change
Also download and run click here
you could have a lot of nasties on board.