Go to this site and it will tell you all you need to know whats works in the backgroud
There are so many things that can be disabled in services
Run>services.msc
http://www.blackviper.com/index.html
Looking at your startup....in msconfig.....I personally only have 1 or 2 things starting up.
Disable all apps that you see there except you antivirus.....you might have two or three that apply to your antivirus.....and if your have a firewall program
All other programs aren't needed.....they just take up resources when starting up. Most programs like Microsoft Word likes to enable itself on startup when installed....alot of programs wants you to have them in your taskbar. Quicktime does this everytime you launch it.
No need to have those programs taking up resources.....just put a shortcut on your desktop for these types of apps.
Empty your temp files....do a diskcleanup and run a defrag......You might need to run scandisk before defrag.
Adaware and Spybot.....run these programs at least once a week.....regscrub is another good little utility to use.
Also....Ram is cheap....buy some.....I have 1 G on my comp....its the cheapest way to make your comp run quicker.