Emergency help needed pleaseeee save my plants!!!

left my grow room on thursday morning and all my week old little sprouts looked fine and healthy (easyryders under a 4001 HPS 20/4) , and i tin foiled the area which they were kept that morning, Today i have came back to find all four of my easyryders flopped down in the soil and too weak to even prop up. a couple i threw away straight off as they seemed beyond salvaging, two are currently propped up with tooth pick. . . Any help would be amaing as this is my first grow and i cannt afford any more seeds.. . . . . .
1. how can i save these two remaining plants??
2. what was the cause of the plants all flopping over weakly?? over watering ?? light too strong?? tin foil bouncing light at the stem and weakening it??

Did you water them? Add any nutes?

Light might be to low and hot. And I would ditch the foil. Might be creating hot spots. That is the problem with foil.

watered them about a thimble full of water twice a day, kept them about 20inch under the light, didnt give them any nutes as i though they were too young, maybe ventilation
(or lack of) may have been the problem i havent got a fan in there yet and the rooms abit stuffy . . . . rekon the remaining two stand a chance being this weak at such an early stage?

K. Well stuffy might be the problem. You need a way to take air out and bring new air in. Everything eles sounds rite. Oh what soil?

multi purpose compost mixed with vermiticle (im sure thats not how its spelt!) bt last night the two remainging plants were transported into a soil/perlite mix as i thought it might be better

sounds like the seedlings are dampening off, meaning the stem rots in soil that is too wet. You need to make sure to let them dry out a bit before watering, they really don't need as much water as you might think,

Well sounds like your good on the basics. Only thing left is room conditions. Try opening the door when light is on. Or open atleast every hour. Till you can get something to change the air. Sprouts should come back in a day or so.

over watering must be the problem !! think il give them a water bottle cap full a day should be enough to save the other two i guess, first time grow learnt my lesson i guess !!

You do have drain holes in the bottom? Soil should be dry on the top and a little moist about 1/2 inch down before watering. Water maybe every other day

might be too low humidity, i had this on my first grow, opened the tent to find all my seedlings were dead (well i thought they were anyways), consulted the trusty bible to find that low humidity may be the problem, misted them regularly, and in a couple of days they were starting to prop themselves up again. hopefully thats your problem.
if not then your probably looking at dampening off as warlock said, which unfortunatly means its time to buy new seeds