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check the posting "No module named psspy with psse33" or search the forum for past postings. psspy.pyc is located at the folder "\PSSPY27" in your root PSSe directory ("C:\Program Files (x86)\PTI\PSSEXplore34 ??)
To your second question related to "No module named excelpy": apparently PSSEXplore34 installation is missing excelpy.pyc. Let me know your email so I can send it to you.