Win32 API Programming

I want to get the file names (with full path) which are opened in the desktop. For Example if I am working in two files “c:\test\test.txt” and “D:\Documents\resume.doc”, I should be able to get the names of the files in whidh I am working. Is it possible through VB API Programming?
(At present I have got the windowtext and its corresponding process. But I need the file path.)