Thanks BobRodes for that indepth explaination but as I am very new to VB.net I am still having some problems. I released my com object correclty but excel is still running in the background. Any way of shutting it down after releasing my com objects? and in a relate topic. Am I releasing them correctly? Got this from another thread.
Code:
Try
    System.Runtime.InteropServices.Marshal.ReleaseComObject(obj)
    obj = Nothing
Catch ex As Exception
    obj = Nothing
Finally
    GC.Collect()
End Try