I keep getting message flashing on screen saying WiFi dongle removed and WiFi dongle detected.

Do you have a WiFi dongle connected to the TV?
If so, it would appear it has a bad connection and needs to be reseated (unplug->plug back in).

If that does not fix the issue, the dongle may be faulty.

Run a malware or antivirus program. It should not be in the middle of the screen if it was a legitimate program.

Dust in the USB socket can cause false indications. Blow out the USB socket and try.

Take it back to the store you bought it from, and ask them to fix it or replace it for you.

without any info,,i;e,,make,model,year,
problem,,WHAT KIND OF ANSWER
DO YOU EXPECT???

The WIFi dongle maybe loose or has lost its settings.

Make sure it has a good line of sight to the router and is not hidden behind the TV.
You can set up the settings manually
.The other thing which may help is to go into TV menus under network and change from 'manual' and use your own details;
Try these settings;
IP - 192.168.1.100
Subnet - 255.255.255.0
Gateway - 192.168.1.1
DNS - 8.8.8.8

hi!i have just the same problem,i made a factory reset and it looks like it helped no more flashing message

Che\k in device manager if the dongle is working properly. For hat in run type "devmgmt.msc" and find the dongle and double click on it. If it says some problem try re-installing the drivers..if it says device is working properly then restart the computer and search for the wi-fi. If it still doesnt recognise take the dongle to a hot spot like a cafe and check if it can detect wifi. If it detects else were its and issue with the wifi at home..if it doesnt recognise the wifi in hotspot its an issue with the dongle.

Hope this helped.