I have an inspiron 3721 17R , bought it from a friend. It runs windows 7. It has new dell adapter and an used dell battery (with dell name on it)
The BIOS shows 90W for the adapter so it seems recognized. However,
a/ When boot, the screen says battery not recognized, and will not be charged. I have to press F1 to continue
b/ after logon to windows, the battery icon says plugged in not charging.