When loading the file from the blender file browser uncheck the Load UI checkbox, which is on the left hand side in the toolbar, to ignore the layout in the file to be loaded:
Note: that this will keep the UI of the current file. It may help to reopen the startup file (Ctrl+N) to restore your default layout, and then open the file without loading the UI.
You can also go to File> User Preferences> File and uncheck the Load UI checkbox in the Save & Load section and save your user settings so that this is the default behaviour for blender when opening files:
In newer versions you need to click on the gear on the top right of the window to see the LoadUI option.