LG 26LG30 screen suddently went blank. Light flashing blue/red

I can only assume you mean that the power light is flashing, not that there is a flashing light showing on the display panel.
The speed and number of flashes you get is the troubleshooting code to tell what's wrong with the set. More info is needed.

check mother board.

Hi, Ephraim. The flashing red light indicates that the device is showing "low battery". It could be that the LG phone charger fits the charging port on your bluetooth headset but it is not compatible with your device. In order for you to know that it is charging, the device should show a steady red light(means charging).
Please take a look at the table reference below.
----------------------------------------------------------------------
•With the Charger Plugged In
______________________________________________________________________
•Headset Indicator Headset Status
Red-----------------------------------------------Charging (battery level less than 50% charge)
Yellow-------------------------------------------Charging (battery level more than 50% charge)
Green--------------------------------------------Charging complete
----------------------------------------------------------------------
======================================================================
======================================================================
======================================================================
----------------------------------------------------------------------
With No Charger Plugged In
__________________________
Headset Indicator Headset Status
______________________________________________________________________
Off ---------------------------------------------Power off
Three blue flashes------------------------Powering on/off
Steady blue --------------------------------Pairing/connect mode
Rapid blue/purple flashes -------------Connection successful
Quick blue flash --------------------------Incoming/outgoing call
Slow blue pulse --------------------------Connected (on a call)
Slow blue flash ---------------------------Standby (not on a call)
Slow red flash ----------------------------Idle (not connected to phone)
Slow purple pulse -----------------------Connected call muted
Steady red ---------------------------------Attempting to connect
Quick red flash ----------------------------Low battery

Note: After 20 minutes on a call or of inactivity, the light stops flashing to conserve power, but the headset remains on
----------------------------------------------------------------------

Hope that'll help you in some way.
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Switch off the TV manually, switch off the power outlet, remove plug and retry after 48 hours. Then if the problem persists, this might need attention by a qualified service technician.

Check the main AC fuse first, it shoud be located close to where the power cord goes into.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

you have a bad cap in the power supply
these are can shaped device thet if bad will vent anf put up on the top the valoue is wrtten on the side trplace them and you should be good to go

Power inverter board is dead.Need anew one.

Sounds like the Power supply module. I would take it in to service center ASAP!

Your Lcd Projector Lamp/DLP Television Lamp went out

its about $165-$200 to replace if not under warranty