I had a similar issue with a slightly newer Dell Latitude, except it would constantly show 5% battery and would refuse to charge regardless if whether the laptop was powered on, sleeping, or completely off. The charging LED would light up for only 2 seconds, and that would be it. Interestingly, even though this wasn't a Dell battery, BIOS did not mention anything about a non-genuine battery being installed. Tricks mentioned here didn't help. What I attempted was a risky maneuver, but it worked. I swapped the battery back to the old Dell one, powered the laptop into the BIOS, went to the battery information section and plugged in the charger. Then, without powering off the laptop, I swapped the battery back to the new one, and it immediately started charging. I went through a full charging cycle, from 100% to low battery power-off event in Windows, then back up to 100%, and everything seems to be working well! Of course I should underline it again that this is a risky, dangerous maneuver that carries a real...