I've not used Inventor in the past but have used Pro E and SolidWorks. I'm going through the Inventor 2012 Tutorials on a 30 day trial version of the S/W. While editing a sketch (sk1), the instructions refer to going to the Options folder of "the browser". I cannot find anything called a browser or an Options folder in any of the ribbon panels, pull downs, etc.. When I go to "Help" and search "browser" I find a listing of several browsers and the functions they contain, but not how to find the browser.
I am envisioning that this "browser" is a window/panel on the left side of the screen, similar to what Pro E and SolidWorks use, to enable the designer to track and edit elements of a model after it is created. I may be wrong about this, but at any rate, the time I have spent searching for it has been somewhat wasted.
I apologize if this is a silly problem to experienced Inventor users, but I would appreciate some help, as I am not able to proceed through the tutorials. I may have to recommend SolidWorks even though we have several seats of Autodesk S/W.
It sounds like maybe you've accidentally closed the model browser. To get it back you can go to the View tab on the ribbon and click the User Interface dropdown, and the set the check box for the Browser.
If this is not what you're after, you might post a link to the tutorial page you're referring to and/or a screen shot of your Inventor screen.