Alienware m17x r2 - Dead Battery, Not getting power after upgrading

I installed a new 750g HD into primary slot and moved the original to the Slave slot; also replaced the factory DVD-RW with same model. Preparing to do a fresh install from the original W7 disk, I started my system up and was too tired to recognize the familiar post-startup beeps telling me my PS wasn't recognized. Correct PS w/blue light on. I was taking too long to get things going (a little overwhelmed with how to do install -- it's been a long time and things have changed), I exhausted my battery. And my computer is dead. I tore it down to parts to take a look at the DC Power jack and there it sits. All I can see is that there was a little bit of battery acid on the side of the jack, which I wiped off with a soft brush. Could that be doing it? I doubt that's the only problem if it is one at all. I, like others, have been plagued with this problem from the beginning, but it's always resolved itself before the battery died. Where do I go from here?? What are all the possible problems? Will do the bios update and turn off the thingy that judges my PS once it's going. And thinking of booting off the old primary-now slave drive to format the new primary drive so I don't have bios issues when installing new windows. But main problem ... how do I get power to it first??

 

You could try replacing the DC jack 1st, then adapter. The worst scenario would be a motherboard replacement.