If you have bought any Lumia phone, you have familiar with the feature called project my screen. This feature allows you to project your Lumia screen to any monitor, Tv and other devices. Although it's quite easy as it only requires your nokia Lumia data cable, project my screen app for pc and obviously Lumia phone. But sometimes it shows nothing when you connect your phone to the pc. In order to fix the problem I am going to give a step by step process to fix it. Let's see the following steps:

STEP 1: Plugin your Lumia phone through data cable.

STEP 2: Go to the device manager and uninstall all the mobile drivers.( it can be seen with the mobile name.)

STEP 3: After uninstalling, unplug the phone and restart the computer.

STEP 4: Open the project my screen app on pc and plug your phone again.

STEP 5: Now your pc will continue to install your phone drivers and after the process is over your phone gets notification whether you are allowing your phone to project the screen on pc.

STEP 6: Tap yes to proceed further and now the phone screen can be seen with the help of project my screen app.

Even after follow the above steps the problem remains the same then I recommend you to update your drivers connecting your phone to pc.