I want to prevent Google Market from upgrading to Google Play store my HTC desire HD wont download from the Google Play Store , but will from the Google Market.
How do I stop the phone from automatically upgrading ?
If you're rooted, then use an app to freeze the MarketUpdater.apk app.

You can also remove that app from the /system/app directory.

Without that app, the market/Google Play won't automatically update.

There is no way to prevent market updates without root.