Latitude D630 battery issue

I just got this computer last month, and love it except for one thing. I ordered it with a 9-cell battery because I heard so many good things about it's battery life. The problem is that now the battery seems to be dying quicker and quicker. I used to get about 4 hours of battery life (considerably less than other D630 owners have reported but I was content with it) Now I only get about 2 hours of battery life at 95% charged with Wi-Fi on and at half brightness, and QuickSet keeps popping up this box:

The end of it's useful life-The computer's only a month old.

I thought it might be a Vista battery meter thing, but when I logged onto Linux Mint, it also displays a box:

I also got this information from the battery meter in Linux (Couldn't get anything like this in Windows except for Dell's pitches for me to buy a new battery :

Now I'm wondering if my warranty would cover this battery issue, I mean it isn't normal for it to die so soon, is it? And has anyone had trouble getting a replacement battery under warranty?

Thanks for all the help given to me so far

 

Don't know, but... here's some info about having it replaced under warranty:
http://mikelococo.com/2007/03/d620-battery-life/

 

Oh thank you! Checked the battery and 5 lights appear-not good. I guess I have to call tech support tommorrow.

+Rep.