You can turn off the Sidebar and Vista Aero, and that should help somewhat. http://www.howtogeek.com/howto/windows-vis...-windows-vista/
You also have a LOT of services. Is the status of them all 'running'? Because if so then that's taking up a lot of resources. What you need to do is figure out what certain services are for, and whether or not they can be disabled. This site actually has a list of startup programs, and whether or not they're essential. http://www.bleepingcomputer.com/startups/M....exe-17198.html
I don't know if there's any easy way to do this, as it's usually a long and tedious process, searching for them one by one. I use WinPatrol FREE which has a filter that doesn't list Windows services. It make things a little easier, but I'd still suggest being very careful. You don't want to accidentally disable an essential Windows service.
There are however certain obvious things that you can close when you're not using them. MySace IM for example. There's no reason to have that running if it's not being used. Research them and figure out what's what, and if you can turn some of those programs off it should definitely help you.