Computer won't boot up

Hello,
I got a message saying not enough memory and that I needed to run disk cleanup which I did. got home later that day and computer was off and will not boot up. I believe the hard drive is turning but Im not getting a light on the front. I pulled my memory cards and turned on pc and I get continuous beeps so Im assuming my mother board is good. I pulled the processor fan and turned on and the processor begins to warm immediately so Im assuming the processor is good. Before now Ive had NO issues with this computer. Im not a computer person so I dont know what to do from here. This computer is just over a year old so I want to salvage what I can. Is this the hard drive itself? I need major assistance here!!!!!