Laptop won't run without AC even with full battery...

I just purchased a refurbished Dell latitude CPi, bought a brand new battery for it. The laptop runs just fine with AC power, and when I look at the battery meter in the taskbar is says 100 percent. But yet, when I try to make it mobile by unpluggin it from the AC cord it instantly shuts off, almost as if it's shorting out. I will charge the battery full, and test it by taking it out and checking the indicator on the battery which lights up full, but then the computer still won't run off of it. If anyone can help me with my problem it would be greatly appreciated, thank you

 

bump

 

Sounds like a bad battery. See if you can borrow a good one to try. If you bought from Dell, they will stand behind their refurb.

 

Check the contacts in the battery compartment. See if they need to be cleaned or if they are pressed in to far.