Projected Coordinate System - Matching Up Issues

Hi All,



So I have a little problem (I am coming from a different GIS program and am still learning with ArcGIS 10). Anyways, my problem is that I have several shapefiles (all with the 1927 Datum), and I put in a basemap (the World Topo Map) as the base layer. Anyways, all of my shapefiles match up with one another, but the basemap is slightly off to the left of where my data should be....


Anyways, sorry if these are stupid questions, hopefully I'll get this program understood pretty soon.




Thanks all of you :)

Matthew