By default, some installation of Windows 8 will show a checkbox on the top left corner when you hover over to select a file or folder. This could be helpful to identify the current selected item, but it is not the default behavior on any previous version of Windows (including Windows 7). So if you don’t like this, there are ways to turn this check-box off.
Here is How To Turn Off Check Box when selecting an item in Windows 8
Go launch Windows Explorer > View > Options
Under the View tab, find a setting under Advanced settings: > Uncheck “Use check boxes to select items”. That’s it, click OK to apply the setting, you should no longer see the check box appear when you are making a selection.