First open up start menu and type in "services" if you use the English version or "服务" if Chinese. Services should be returned as the first result and hit enter to open the service panel. Now that you see a long lists of services hit "Name" to let them be arranged by name, then drag the "Name" list longer so that so can see their full names.
Now the tweaking part. The good thing is you only need to mess with a few services to get the system faster, the bad thing is disabling certain services may have unexpected effects. I will tell you what you should disable and explain the reasons and possible consequences.
Find "Windows Search", double-click it, choose "disabled" from the drop-down dialog box, then click "stop", after it is done click "OK" to return to the service panel. This is my procedure to disable a service once and for all. Disabling "Windows Search" does not stop the search function, but it disables the indexing service. All I have to say is the indexing service is not worth it at all. If it is not worth it, kill it.
In the same way stop "Readyboost". Why? Simple. If you have money to buy a 2G Flash Disk, you have money to upgrade your memory to 2G. Even if you cannot upgrade, Readyboost will not really make your computer run faster. Whenever you choose to see the properties of a flash disk, the system will take some time to check if its performance suits Readyboost. This extra checking time makes working with flash disks a pain. Also using Readyboost will make the system constantly write into the flash drive thereby shorten its life span and make the system slower.
Stop "Windows Error Reporting Service". Are you even asking why on this one? Since when can Windows help you?
Stop "Windows Defender". Yea I think Windows Defender is pretty much useless once you have installed an anti-virus program. And it updates frequently, LOL! Stop it from lagging your machine!
The other two are of your choice, there are serious consequences once you stop them:
"Windows Update", yes and right, you should seriously consider stopping it. Each time it tries to find update CPU goes up to full. If timing isn’t right this can mean hell to you. The consequences, do I really have to explain?
(Not recommended) "Superfetch". Superfetch does exactly what some people complain about. It finds your favorite application and read it into memory cache as long as you have memory. Have you noticed in Vista that your free memory are usually less than 10 regardless of how much memory you have? This is the culprit. Each time you start your system, or each time you quit a game or something, Superfetch makes sure the hard drive works its ass off to feed the memory. The good thing is your favorite applications will load faster (except games). The bad part? Some people complain their hard drive works all the time. My personal experience is Superfetch is what makes Vista Vista. Without Superfetch Vista will be exactly like XP in the core. Disabling it gives you an XP-like experience. So it depends on what you want to experience.
I hope you can feel the speed differences after my service tweak. But if you don’t reading it isn’t really not worth the effort.