Just a quick post on something I ran into lately with my Dell Precision M4500 laptop (monster laptop!).  I noticed the little icon in the system tray for the power options was stating that it was “plugged in, not charging”.  I don’t know why it was stating this, but I quickly found a fix for it on the net.

I found the fix in this forum on CNET.  Here’s the fix:

In order to correct problems with the battery's power management software, follow the steps below.
1. Click Start and type device in the search field, then select Device Manager .
2. Expand the Batteries category.
3. Under the Batteries category, right-click the Microsoft ACPI Compliant Control Method Battery listing, and select Uninstall .
WARNING: Do not remove the Microsoft AC Adapter driver or any other ACPI compliant driver.
4. On the Device Manager taskbar, click Scan for hardware changes .
Alternately, select Action > Scan for hardware changes .
Windows will scan your computer for hardware that doesn't have drivers installed, and will install the drivers needed to manage your battery's power. The notebook should now indicate that the battery is charging.

 

And it did work.