i'm on scene three and i'm not getting any further in the crime scene the arrow turns green but i've collected everything it will let me and i've got to the point of talking to the nurse at the hospital but i can't get any warrants yet! PLEASE HELP

Welcome to the forum. :)

Did you try asking for a hint in the game? What did it tell you to do next?

It's hard to know what to suggest without knowing what you've already done. :( You're sure all the evidence you've collected has been processed appropriately in the lab?

If all else fails, this walkthrough might help.

Helppppppppppppp, csi 3 dimentions of murder
 

Im on the 2nd case, but cant get past a certain bit. Im on the bit were maya and chris are in interrogation and ive collected all evidence and processed it. But i got a flash drive thing off maya and ran it and it says "run this by brass" but when i go to brass its just asking if i wanna talk to a suspect :s, ive used all hints it wont give me anymore. Anyone helpppp?

You might have missed something small before this point. This walkthrough might help you figure out what's missing.

Try picking up the nurses cup once he puts i down you can get finger prints and dna from it!!! It took me forever to work it out! Hope that helps:d

Try runnig it through the finger print computer(cant think of its proper name right now)

if you mean the criminal fingerprint database it is called A.F.I.S