If you sold the shares which are in your demat account then yes at whatever rate you have sold will be credited to your account.
Yes, anytime you can sell. For example, if you buy a stock for Rs 100 and now it is trading at Rs 90, you can sell at 90. But people keep on waiting to see that this stock may go up. Interesting thing is if the stock somehow reaches Rs 120, now they will keep thinking that i can get more profits. That is stock market. So my advice is to follow strict stopp loss and targets. Happy trading http://niftyoptionscallputeasy.blogspot.in