Sorry for the new post, but I need a new look at the error I am having. I have a vb.net application that used to work, but now it doesn't. Here is what is happening.

Public ExcelApp As Excel.Application
' This statement executes, but ExcelApp is not created
' properly. All the properties and methods have 
'<error: an exception of type: 
'{System.InvalidCastException} occurred>
ExcelApp = CreateObject("Excel.Application")

'If I try to run the following, I get
'QueryInterface for interface Excel._Application failed
ExcelApp.DisplayAlerts = False

I have tried creating ExcelApp with CType and DirectCast. Neither works. I am using Excel 9.0 Object library with Excel 2000. Updates have probably been run on my machine, but I don't know which ones. The app has stopped working on another machine. It was upgraded to Excel 2003, but gets the same error. The program still works on some of the machines at my company. Do I need a higher version of the Excel Object Library. If so, where do I get it? I really need to get this working. I appreciate the help.

Thanks.