E1505 will not start

I have a nearly 3 year old E1505. About two months ago, the battery started to fail. I was getting the message that the battery was low, but could charge. Then about one week ago, it stopped turning on, even when connected to the AC adaptor. I bought a new battery, but it isn't solving the problem. When I press the power button, all three lights in the top center turn on for a second and it sounds like it will start up, then nothing. The only thing that remains lit is the green power light on the top right side. When you press the power button again, it makes a low falling whine and the light goes out. The adaptor is working (light is on) and the new battery is fully charged (all lights are green). Some others have suggested in other posts that situations like this are probably the motherboard...Is this likely the case here?? System is not under warranty and I really would just like to get some of the information off the computer then purchase a system that actually works, like an HP! Thanks for any advice!