I tried to install Rx 550 in my CPU but it does not work, the other card 710 is detected but Rx 550 does not work. I use dh61ww motherboard with 16 GB RAM and i3 second gen processor
What motherboard and CPU do you have? Are you trying to run both cards at the same time? If so, your motherboard may not support it.
If you are replacing the 710 with the 550, then you should do a clean install of the drivers. Use this DDU tool to uninstall all of the old drivers, then get then install the recent drivers from AMD.
Yes it is installed properly the I can see the fan working but no display is detected in monitor.should I completely uninstall nvedia driver with the application you have said and again install 550 driver .
Your motherboard may require a BIOS update to run that GPU. If this gets the card to display then the next step is getting the newest driver from AMD and deleting the Nvidia drivers from the Control Panel.