@khurshid...Go to Wallet, at the amount of Steem Dollars klick Market. There you can buy Steem for your Steem Dollars. Then go to Wallet, at the amount of Steem klick Power up. Then you have Steem Power. You can not sell Steem Power for 3 months. Why Steem Dollars is decreasing I don't know. I thought it's the same value like the real Dollar, but it is not. I will follow this to understand it better.