XPS M1530 not charging

I've tried getting a new ac adapter, but it doesn't solve the problem of my computer not charging.  The second the adapter comes unplugged from the computer, the power goes out.  Any ideas on how to fix it?  Do I just need a new battery pack, and can I put it on myself?  Should I send it in to Dell or should I take it to some other place?  I just want to be able to take my computer places!