HELP! Plant taking a nosedive!

Setup:
Indoor grow, (2) 150W HPS, (2) 42W CFL, fan, Miracle-Gro soil, bagseed, yeast/sugar for CO2.

She is about 4-5 weeks into flowering and up until now, has had no problems. Topped her once, growth was slow after moving plants, but regained her strength.

Now, I woke up this morning before work, turned on the lights and the plant looked fine. Got back in the afternoon and she looks awful. All the leaves are drooping down, some of the branches have slumped over too. The leaves feel extremely thin and the plant is showing no signs of life. I have been watering it every 2 days and just watered it this afternoon.

would need some pictures for people to know for sure. hows it showing no signs of life?

I have no digital camera, so no pics.

The plant went from looking full of life to looking dead in the matter of a few hours. I woke up this morning and the plant looks the same. All the leaves feel thin and light and are the entire plant is completely flaccid. All the leaves are drooping down and whole branches are drooping down as well.

sounds like they got too hot. what are the temps lights on and lights off ?

also soununds of over watering,water itevery 2 days are so

if you could find a way to post pics that would help greatly, until everyone sees the plant, its a lot harder to diagnose. But okay, off the top of my head i can think of 3 things, 2 of which had been said (Too much watering,temperature) with the watering, make sure youve got proper drainage at the bottom of your pots or you are going to end up drowning the plant. If theres drainage, a general rule of thumb is water every two days, but also, if its still moist about a pinky length down, theres no need to water. Let the soil completely dry before watering. Temperature should be around 75-85, although im thinking that it would be alright with lower temps, most people around my area have plants outside and they live fine through a light frost. If it was too hot, your soil would be getting dry extremely quick, and if your watering only every 2 days then thats not the problem. Too much Nitrogen can cause your plant to turn a dark green and become wilted and flacid.