Hi Valerie,
I'm not exactly sure what you are asking, but here are some thoughts.
Does the shapefile you are using have a defined coordinate system? You first have to define a geographic coordinate system and then project the shapefile. Projecting a shapefile that doesn't have a defined coordinate system causes mumbo-jumbo.
Are you using a downloaded or a self-generated shapefile? E.g. Tiger/Line Census files come with a pre-defined coordinate system (NAD 1983, I believe), but are not projected.
The "Define Projection" and the "Project" tools will be helpful in achieving your goals.
Hope this helps.
arina