I have a blank map, I've set the data frame to the same projected coordinate system as the data I'm going to add. I have added one shapefile and it looks good. When I wave the cursor over the map the decimal degrees displayed in the lower right corner of the data frame are correct.
I then attempted to add a Excel table that has lots of points with the decimal degrees for each point. I added the table, and used the Display XY Data option to display the points. The resulting points do not overlap the first shapefile, even though the two are actually just about identical. I've checked the projected and geographic coordinate systems and they're the same.
When I zoom in on the layer with the points I find that in the lower right hand corner of the data frame it registers everything as being at -85.489, 0 decimal degrees, which is clearly wrong. The measure tool shows that the points are mere millimeters apart, which they're not.
Based on similar question on this site I tried using the project tool on my points and projecting it into the format it already was in (i.e. the same projected and geographic systems as the shapefile) that didn't work, it just wound up warped.
What has gone wrong with displaying my data?