Sony don't actually tell you but you are supposed to extract the battery while you use the mains adaptor, otherwise the battery pack fries.

You have got to be fucking kidding me.

There are times with this laptop... because of its inane power-switch system that's all software controlled... that there is NO WAY to reboot the unit without pulling the battery. Sometimes when Windows really screws up, everything is hosed and no amount of button pressing on this laptop will get it to shut down and restart. Only recourse is to pull battery and mains power and re-insert. Done it dozens of times, NEVER ONCE paying attention to the order of which items I'd pulled.