Re: what processes to keep running?
My lord you have quite a few on there. I don't think there are many people out there who can look at that list and tell you what you don't need because different programs use different processes so you really can't know them all.
The best option for you may to be look at programs that start up when your computer does and tell them to not to. I swear every programmer thinks their project is more important then everyone elses so they all try to start when windows loads.
Look in places like Start menu> all programs> start up and delete shortcuts in there, anything in there starts up when windows loads. Then look at programs like itunes, winamp, printer software, adobe items, and basically anything down by your clock and tell them to not start up if your not going to use them. Messenging services like Yahoo and Windows messenger, and AIM all like to hang out down there. All of which can be told to shut up and only load when you want them.
So basically the more programs open, the more processes will show up. So close programs and you should be good to go; or at least better off then where you are now.