Help

[hwaiii50]

I have a 38in Sony KV-36XBR400 which I've had for about three years. About a month ago, it started to shut off after being on sometimes for ten minutes or a couple of hours. When it goes off the stand-by light comes on and blinks five times. The sound works fine. Please give me any suggestions you might have. I can't afford to pay to get it fixed right now with Christmas just around the corner. Thanks a lot. Patti