If any one can explain to me the difference between sccm, wsus, gpo, sce "system center essential", in sw and patch deployment.
With GPOs you can only do basic software distribution tasks (i.e. automatically install some software), and you don't have much control on this process.
With WSUS you can do all of your patch management, but it's not a full-featured desktop management solution.
SCCM is exactly this: you can manage almost everything on your network using it.
System Center Essentials is a reduced bundle of SCCM and SCOM, tailored to small- and medium-sized companies.
You can find a product comparison between SCCM, SCOM and SCE here.
WSUS is the Microsoft's basic offering for enterprise OS and Microsoft application patching. It is capable of connecting to Microsoft's update catalogue, has a small amount of configuration around scheduling rollouts by groups etc, and limited reporting details on patch deployment.
SCCM (System Centre Config Manager) is the replacement for SMS, it has SCUP (System Centre Updates Publisher) as one of it's components. This builds on top of the WSUS infrastructure and components and gives you massively more configuration and reporting, as well as having the ability to connect to other vendors' update catalogues (Adobe, Dell, HP, etc) and also deploy your own custom patches for any apps. In addition to patching, SCCM also retains all the software packaging, and deployment, OS deployment, etc of SMS.
GPOs (Group Policies) can be used for software deployment, but doesn't have any special patch-specific functions, and has very limited info/reporting on deployments
SCE (System Centre Essentials) is a cut-down SCCM for smaller businesses that shares much of the functionality of it's big brother.