Windows 7 was introduced with a new feature which enables you to automatically dock and resize window when you drag the window to right / left side of the screen or maximize a window by just dragging it to the top. This feature seems cool but something its bit annoying when you are working with too many windows open. So here is how you can easily deactivate this auto resizing feature of Windows 7.
Step by step process
1. Click on Start button and Type Ease.
This will bring you the option "Ease to Access Center". Click "Ease to Access Center".
2.From Ease to Assess Center click Make the mouse easier to use.
3. In the next Window enable the checkbox Prevent windows from being automatically arranged when moved to the edge of the screen.
4. Click OK
and you're done!