Upgraded Windows 7 to Win8 earlier this year, and last week upgraded to Windows 8.1. (Lenovo T60) Had no problem with battery usage when on Win7 nor Win8. After about a week of Win8.1 on my system, the battery stop working, while the system was on. The orange batt. indicator just keeps flashing. The system does not charge the battery (even though I know there was life in it). I installed a known good fully charged battery from another T60, it worked for aboute 40 mins then it instantly died in fron of my eyes. The system now shows the same orange flashing batt. light, but it is not charging. I know both these batteries are still good, they just appear to be dead. My research suggest that the new Win8.1 may not have updated the battery driver to Win8. I have since done that. Same problem. Research i s also pointing me to some 'smart chip' on the batteries that need to a reset. Is this possible ?? Does anyone know a process to reset the 'smart chip' on these batteries (fru# 92P1139) ????