I just got a Samsung LN40A500T1FXZA 40' from a friend. He was going to throw it out but I told him I'd take it... Anyway... I am having a problem with it. It is pretty much a combination of all the problems. Red Flashing light on the start-button. Also audio but no video. I don't know what the red flashing lights mean.

It may be in the safety shutdown due to detecting of the shorted circuits (bad inverter boards), or failed power supply. You can disconnect the power cables to the inverter boards to see if the light will stay green.
Please read my guides to get some understanding how it works if you are going to DIY repair:
Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Parts: http://interliquidparts.com/

Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com, just make sure to use caps with low ESR, 105c, high ripple current and long life rating such as PANASONIC FM or FC series.
Please post back what you find.

The tv have 2 long LCD inverter boards are dead.These 2 long LCD inverter boards help the tv LCD screen panel to have a backlight to produced a picture.That why u have audio only no video.Tries websites like Shopjimmy.com,Ebay.com to buy those 2 long LCD inverter boards for the replacement.