HPS trouble

I need some help from someone who knows more than me. I don't know why but my 400w hps won't turn on, it acts like it wants to (making the sounds) but for some reason the light won't come on. It did this for a couple days about a month but ago all I had to do was toggle the switch but now it won't turn on at all. Could this be the just the bulb or is it the entire setup. It's a Hps kit from HTG supply. Please help I'm being forced to use CFL's until its up and running again

if u here the thing making noise then most likly its ur bulb

Is the bulb or the ballast making the sounds?

get a new bulb, if your ballast is buzzing that should mean it's working...

ya, its the bulb...they sell 250 and 400's at home depot.

yeah the ballast is the one making the noise, guess i'll go get a new bulb. This ones isn't that old, how long should they last?

went and got another bulb, it works now. Finally my plant gets some good light