QUES: This means that it is still possible to sell the code but the range of potential buyers is severely limited as they need to have access to the same video card to activate the game on their end

correct the punctuation.

CORRECTED: This means that it is still possible to sell the code, but the range of potential buyers is severely limited as they need to have access to the same video card to activate the game on their end.

QUES: It was not a solitary scientific existence for him in Terling since he made frequent visits to London where he had duties to perform for many learned and scientific societies

correct the punctuation.

CORRECTED: It was not a solitary scientific existence for him in Terling since he made frequent visits to London where he had duties to perform for many learned and scientific societies.

QUES: In the creation of the heavens and earth and of living creatures including man are Signs

correct the punctuation.

CORRECTED:
In the creation of the heavens and earth, and of living creatures, including man, are Signs