If you have a problem with the Google Play store web site saying “No devices recognised”, “You have no devices” or just “No devices”, then try the following:
1) Load the App “Google Settings”
2) Google Settings->Go to “Android Device Manager”
3) Google Settings->”Android Device Manager”->Deselect “Allow remote factory reset”
4) Open “Settings”
5) Settings->Go to “Apps”
6) Settings->”Apps”->Slide across to “All Apps”
7) Select “Google Play Store”, wait for the “Calculating” sections to disappear, and then select “Clear Data”
8) Select “Google Services Framework”, wait for the “Calculating” sections to disappear, and then select “Clear Data”
9) Open “Google Play Store”
10) Wait between 1 minute and 24 hours for the Google Play website to update
And you should now be able to install applications on your phone or table via the Google Play website.