I have a 7 speed shimano (no front derailler)

I was having a hard time shifting into granny gear - it wouldn't shift just run rough hesitating.

So I pulled up videos on youtube on how to adjust a derailler and I followed them to a "t". Now here is the thing - I was working with my bike flipped upside down resting on the handlebars and the seat. I never could get the derailler to move to the granny gear no matter what I did.

So, I asked my son to run by the LBS and have them adjust it - when he gets there (of course he never checked the granny gear riding - neither did I) - it all worked fine.

So it dawned on me that bike mechanics and ppl in the videos all have a stand where the derailler can be checked in the same position it operates in. Is the fact that I had my bike flipped upside down the reason that it wouldn't hop to the large granny gear? If so, I guess I need to eventually get a stand.

Yes - I'm a newbie when it comes to trying to be mechanical ;P