Everything is running fine, but then,

[Boats]

major stuttering and the FPS counter is jumping (more like flashing) from 8 to 60 FPS. This is while on the tower, and it starts at the beginning of a saved game. That is, if a don't get this stutter at the beginning of starting a saved game then I'm fine. If it's present from the gate then it won't go away, any ideas?
Shutting down some processes helps, but I haven't had this problem until recently, it started off the east coast of Britian.
And as it regards shutting down processes, is there anyway to turn them off permantly, until I need them, at which time I can start them up again? It's a real pain to have to go into the utility everytime I want to run the game and go through the check list.
And oh yes, I'm using XP Media Center Edition (Dell).
As always, thanks.