Toshiba Regza 37in - 37HL17
TV will not turn on - Yellow power ind. Light blinks three times...
Fixed with a firmware update (hard to believe, but true). Search Google for a file named: 2007SEN069.zip (don't worry if the page you find it on doesn't mention the 37HL17 - it worked fine). Unzip the file, and copy the 3 folders and 3 files to the root of a small SD card. The SD card MUST be 2GB or less in size (I used a 1GB card), and it MUST be formatted with FAT-16 (not FAT-32). Mine was pre-formatted as FAT (FAT-16). The SD port is on the back of the TV behind a cover plate near the power cable. You do NOT need to remove the back cover of the TV, just the small cover plate (1 screw). UNPLUG the TV; remove the cover plate; insert the SD card (prepped as explained above); Plug in the TV; Watch the yellow lights blink, then turn blue, then go dark; UNPLUG the TV; remove the SD Card and replace the cover; Plug in the TV; Yellow lights will blink a few times (this is normal); when blinking stops, turn on the TV and you should be good to go. :-)
Pictures attached are from a Toshiba software upgrade bulletin I found online.