Really don't see a lot there unneeded. You might try, as an experiment ONLY the Symantec processes just to see if things are speeded any, then you will know.
What is your Virtual Memory setting?
On Windows XP, look in Control Panel: System, Advanced, Performance, Settings, Advanced, Virtual Memory.
Generally recommended setting is about twice amount of RAM or perhaps less say 1 and 1/2 times the amount of RAM installed.