The battery on my wife's computer would no longer hold a charge and it was time to replace it. We replaced it with a generic brand battery (little more then $100). It charged fine, but then while it was running a message would suddenly pop up, saying that the battery was not inserted correctly and that it had to switch to hibernate mode. The battery light would flash rapidly after this, and it would never come back long or it would go hibernate again. Re-seating the battery had no effect. It turns out that Sony truly has turned evil. They are running a little service that checks whether the battery is a Sony battery ($300!), and if it is not then it kicks into action and sends your machine into hibernation!
After some digging I found this
article, and the fix is easy, the service is called ISBMgr and to get rid of it permanently fire up msconfig like so

go to the startup tab and uncheck the ISBMgr.

Now when you restart it will ask you if you knew that some services where changed, just say yes and it will never bother you again.
Bad Sony. No more Sony for me..