The conversion of the project was successful.

The new directory structure is as follows:

C:/Old_Computer/My Documents/TEXTBOOK/Textbook 2005/PSPICE IN TEXTBOOK -- PRELIMINARY/BUCK CHAPT 6
    Buck converter 1.opj
    buck converter 1.dsn
    buck converter 1.dbk
C:/Old_Computer/My Documents/TEXTBOOK/Textbook 2005/PSPICE IN TEXTBOOK -- PRELIMINARY/BUCK CHAPT 6/Buck converter 1-PSpiceFiles
    buck converter 1.ind
    buck converter 1.lib
C:/Old_Computer/My Documents/TEXTBOOK/Textbook 2005/PSPICE IN TEXTBOOK -- PRELIMINARY/BUCK CHAPT 6/Buck converter 1-PSpiceFiles/SCHEMATIC1
    Buck 1.sim
    SCHEMATIC1.als
    SCHEMATIC1.net
C:/Old_Computer/My Documents/TEXTBOOK/Textbook 2005/PSPICE IN TEXTBOOK -- PRELIMINARY/BUCK CHAPT 6/Buck converter 1-PSpiceFiles/SCHEMATIC1/Buck 1
    Buck 1.1op
    Buck 1.cir
    Buck 1.mif
    Buck 1.mrk
    Buck 1.out
    Buck 1.prb