Dear sir
Here is my question:
In response to the question:"would you mind closing the window?"
Is it ok to say:"yes ofcourse"?and is there any other common reply?
Best Wishes

Logically, the answer to this question is 'no' before closing the window. However, the connotations of the word 'no' suggest that you are not willing to close the window, so many people would answer 'yes' to this question.

Grammatically speaking, the answer is 'no' if you are prepared to close the window.