By default you need to double-click your left mouse button on an icon to open an application or file in Windows Explorer or on your desktop. Double-clicking requires just the right timing (as configured in Control Panel) between clicks to be successful. Double-clicking has never worked well with Windows. Fortunately it's very easy to configure Windows to work with single-clicks.
1. Open Windows Explorer (Start | All Programs | Accessories).
2. In Windows Explorer's Toolbar select Organize | Folder and Search Options.
3. In the Folder Options dialog box that appears, on the General page, in the Click items as follows section, set the "() Single-click to open an item" radio button. Then click on the [OK] button.
Now you can open any application or file in Windows Explorer or on your desktop with a single-click.