I'm sorry to hear that you're having trouble powering on the TV.
When was the unit purchased? If it's still under warranty, you can call 800-SAMSUNG and have a technician take a look at your unit.
I have a TV Samsung Model LN46B750U1F which doesn't turn ON. The power led keep in RED but when I try to turn On using the remote control or tuching the power button, it doesn't turn ON and the power led keeps in RED and the panel is total black without sound.
I have tried disconnecting all the cable include the power cable and then connecting the power cable only, but it's doesnt' work