"...not by might, nor by power, but by My Spirit, saith The LORD of hosts." Zechariah 4:6
Strong's Exhaustive Concordance defines 'spirit' (#7307) as: wind, breath, a sensible or even violent exhalation, which are literal translations. In this same definition the figurative, or symbolic, translation is also given to us: life, anger, unsubstantiality (spirit of a rational being, including its expressions and functions: air, anger, blast, breath, courage, mind, tempest).
Of the 238 times in the OT, only 31 references are to The Holy Spirit of God. Of the 253 times in the NT, 132 references are to The Holy Spirit. The word 'ghost' in the OT referred to death, or giving up the ghost, dying. In the NT the word Ghost is mentioned several times. It is the exact meaning in Strong's as given for the word 'spirit' (#4151) in the Greek dictionary.
Pneuma: a current of air, breath, blast; a breeze; the rational soul, vital principle, mental disposition; angel, demon or God, Christ's spirit, Holy Spirit: ghost, life, spirit(minded).
This means that The Holy Ghost and The Holy Spirit are referring to the same deity. It is impossible for The Holy Spirit of God to lose His identity. When you speak of Him or to Him, He knows to Whom you are referring.