Computer wont turn at all worked fine the night before moniter works no lights dvd door wont open

If the unit worked last night and now it will not turn on then it's one of two issues. first we need to look at the unit are there lights or can you hear a fan running . if so your motherboatrd has failed , and the fact that most dell mobo's have intergrated video you couldn't see anything at that point. two if there is no lights or fans running and you can not open any drives then your power supply has filed . decide witch one and let me know if you dell is still under warranty i can call and do a warranty claim and get them to send parts and a tech if not give me the service tag number and I can find part numbers for you . hope this helps