I've had my XPS720 since December and recently(as in about the last 2 months) I occasionaly have problems starting the computer.

I push the power button the fans turn on, LEDs light up, but nothing else. Some times if I press the power button again the computer will turn off, other times I have to hold it in to turn off the computer. If I cycle it enough like this, it will eventually fully boot up. I have checked all the connections in the case and everything is tight. 

Thank you in advance for any assistance.