i have opened one model and completed the updations. Then, gone to next two or three models. If i want to close the first model, i need to go to window pull down menu and select the particular file. Then it will load and ask if i need to save the changes. My doubt, is it possible to close the model without loading which will take unwantedly more time.
I am not sure what version you are running (you should add that information to your forum profile so other people know when answering questions). However, we added the ability to close documents from both the Windows menu (the location you mention) as well as the Open Documents interface (Ctrl-tab) in SolidWorks 2012. Details are documented here: