Google-forms – How often can a Google form receive responses

You should be able to get a 'fresh' form by deleting the entry rows. That is, select the entire row by clicking the row number(s), right-click, and choose Delete row.

(source)

I just did the following test case:

1. Create a simple form
2. Submit a response
3. In the spreadsheet, select the response row, right-click, delete row
4. Submit a new response

Result: The second response posted in #4 is listed on the first row. The response summary shows only one response.

My initial response is yes.

How? You'll have to look into Google App Scripts. You're probably better off creating a form via script and then creating a function that validates the dates and times. So perhaps the pseudo code would be...

function main() {

    // Get today's date and the final date for the form to accept responses
    //
    var todaysDate = new Date();
    var endingDate = new Date(2014, 1, 31);

    if (todaysDate > endingDate) {
        // form no longer accepts responses
    }

    else buildForm();
}

This is the main idea. Since I'm strapped for time, I'll come back later in the day to clarify this answer if need be. Let me know if you have any questions or would like me to provide you with more examples.

Reference

Google Apps Script: Form API