So it is a 37" 720p LCD panel.
The backlight may have blown out, or the powerboard that supplies power to the backlight.
May not pay to go get it fixed, as a new one may approach the price of the fix, and can get an LED model that is 1080p.
Planned obsolescence comes to mind.
You can try their Troubleshooting Assistant below, but it seems to end in "Repairs needed."
http
/support.toshiba.com/support/troubleshootSelfService?PRDTYPE=TV