Close all not-needed services in window

Goto->Control Panel
---->Performance and maintenance
Administrative tools
---->Go to every service EXCEPT

+ Application Layer Gateway Service
+ Application Management
+ Automatic Updates
+ Backround Intelligent Transfer Service
+ Cryptographic Services
+ DHCP Client
+ Event Log
+ Help and support
+ Human Interface Device Access
+ Internet Connection Firewall
+ Network Connections
+ Network Location Awareness (NLA)
+ Plug and Play
+ Print Spooler (if you have printers)
+ Remote Access Connection Manager
+ Remote Procedure Call (RPC)
+ System Event Notification
+ Task Scheduler
+ Telephony
+ Themes (hey, you don't want to shutdown cute themes right?)
+ Windows Audio
+ Windows Image Acquisition (if you have scanners or digital cameras attached)
+ Windows Installer
+ Windows Management Instrumentation
+ Windows Management Instrumentation Driver Extensions
------> Double click with left mouse button or click right mouse button and select "Properties"
-------> Startup type
--------> Set to: Disabled
-----> Go to
+ Automatic Updates
------> Startup type
-------> Set to: Automatic

NOTE:You should do it at ur own risk.
In general it wont harm your system but if u do any thing wrong it may mess-up your system.