ome meter..How do i use it?

I borrowed an ome meter to see if my 250w ballast is messed up..When the timer turned on today the light didnt, the ballast buzzez when you plug it in but the light will not turn on..I dont think its the bulb.the bulb looks fine but ive never seen what a bulb looks like when it goes bad.So before i buy a new bulb i was told to test it with an ome meter.i got an ome meter so how do i test it?heres a pic of the meter..what settings i put it on and wich prong i use the black or red one?Thanks for any help
http://www.atel-electronics.eu/produkt.php?hash=03904&dispLang=EN

well ohm's are the measure of resistance in a circuit, so really they are for measuring to see how much a circuit is resisting the flow of current, so for a ballast you could use it t check the coil and such with the ballast unpluged of course but if your sure its not the bulb, which i think it might be then you could use the meter to check the voltage at the socket then work your way back to the ballast, with the ballast on the red probe goes in the center of the socket and the black lead you would touch to the threaded side. i dont know what numbers you are looking for but if there is voltage then you should get a new bulb, another test for the ohm meter would be to test the cord going from the ballast to the hood, a reading of 0000 will mean the circuit is open and is ok, some meters say different things like inf- to show an open circuit, personally if i were you i would get a bulb because if the ballast is firing up then 99% of the time its a bulb, ive had bulbs that were bad that looked all black on the inside and others looked new, my guess is that if the ballast is making noise its the bulb that needs changing

yes but it should read 250wtts if thats what the ballast isanything less wont fire the bulb

Thanks for the info sam.The ballast is 250w ive been useing it for 3 months..I just got home and i swung by a lightshop and bought a new 250w bulb..it doesnt quite look like my old bulb but it fits in the socket perfect and i plugged the ballast in with the new bulb and it doesnt work..So i think im fucked and my ballast doesnt work..Is there anything anybody can think of why it would just stop working?it still makes noise when i plug it in just doesnt start the bulb anymore....This sucks so bad its almost 8 weeks of flowering and the hairs are just starting to go amber..I think i have to harvest early.....

The capacitor or the ignitor in the ballast box could be bad.If it buzzes when you plug it in ,it sounds like the coil is still good.You can buy replacement ballasts from WWW.1000bulbs.com. Look under flourecent and hid ballasts.OPH