VB.NET Excel All Versions

Ever wonder how do write a .Net Excel app that allows deployments in all platforms. (Excel 97, 2000, 2002, 2003)? Microsoft made a huge changes in office 2007 including the extension of the excel. It is now .xlsx, no longer. xls.  I am uncertain whether my solution works for Excel 2007. Anyway the answer to make it works in all version is late binding.

One of the disadvantage of late binding is you lose all the intellisence. Use early binding to use the intellisence and change the code to late binding syntax before deployment.
Early binding example:

Before deployment, change it to late binding as follow.