QUESTION: Fix punctuation: But they will be downloaded by the user himself
ANS: But they will be downloaded by the user himself.

QUESTION: Fix punctuation: This figure was calculated by the Office of Utility Regulation OUR but did so using the 1999 average price of USD 1650 per barrel
ANS: This figure was calculated by the Office of Utility Regulation (OUR), but did so using the 1999 average price of USD $16.50 per barrel.

QUESTION: Fix punctuation: The convenience of these verbal directives issuing back and forth is obvious
ANS: The convenience of these "verbal" directives issuing back and forth is obvious.

QUESTION: Fix punctuation: Reinstalling Windows solves the problem until next time
ANS:
Reinstalling Windows solves the problem... until next time.