Battery Problems..

Hello there,
I'm new on here and new to using mac laptop that i recently just purchased. I have had it for about 2 weeks now and last night i put it to 'sleep' and when i came back to use it, it had switched itself off and wouldnt come back on. Now i can only use it when my AC adapter. I have also noticed an 'X' over the battery icon in the top corner. Can anyone help me? I heard someting about getting into the firmware options, though trying to do the command at startup, nothing seems to be working. I'd appreciate it if someone could maybe guide me on how to fix this r if i need to go and get a new battery.
Thanks alot.

Jrdn

1. Try Resetting the SMC (for a MacBook or MacBook Pro) or Resetting the PMU (iBook or PowerBook). (Ignore the part about "If the computer has stopped responding..." since that isn't your problem.)

If it doesn't work, and you just purchased it new, call Apple, or take it in.

If this is a new Mac I would highly recommend talking to Apple. They will be able to sort this issue out for you, as it's a new machine it is down to them to fix this.