Referencing the callee

[Hariharan]

Here I have an application which is being called based on SetWindowsHookEx API, and its required to replace a content of the selected text in the calling application on request. How could I get the reference of the textbox on other application. Any idea on this topic would be useful for me.

Can anyone knows how to get the running instance of Word or other application from vb.net.. I am using the code as

Dim eWord as object
eword = createobject("Word.Application")

Also i m using
Dim eWord as Word.application
eword = CType(GetObject(Nothing, "Word.Application"), Word.Application)
But i m taking this type of running instances, sometimes i met an error.. But the above code, it is created a new word instance.. How can i do without using GetObject method..

[Hariharan]

Anyone know how to do the above requirement.