From your snapshot, I believe you are using ArcMap 9.x or earlier.
(Considering your excel sheet is properly structured, as mentioned by Xander) If you are trying to open an XLSX (*.xlsx) file, it might come up with some error.
Try saving it in XLS (97-2003) format (*.xls), and then opening it in ArcMap.
1. Check if there is any special character in the field name and remove it.
2. Use .xls format
3. Try to save the data in .csv or dbf format and then open it in arcMap.
Besides special characters in the field name spaces are a big no-no even on the end of the name. There is also a limit to the number of characters in the field name. Numbers can be used in a field name but not as the first character. Check out http://www.esri.com/news/arcuser/0312/best-practices-when-using-excel-files-with-arcgis.html for more information on using Excel files in ArcGIS.