Took me a while, but I found a solution that worked for me. Recently upgraded my hp 8510w laptop from Vista Pro to W7 Pro via clean install. Same issues here: "plugged in, not charging". Here are the steps I went through to get it working: 1) Disconnect AC 2) Shutdown 3) Remove battery 4) Connect AC 5) Startup 6) In Device Manager under the Batteries category, right-click the Microsoft ACPI Compliant Control Method Battery listing, and select Uninstall. Do this for each instance. (I had 2 batteries installed, so 2 instances. Most users will only have 1). 7) Shutdown 8) Disconnect AC 9) Insert battery 10) Connect AC 11) Startup Hopefully, this will work for others!!!