Updates to this story
A problem with a bug in a tool in Windows 7 has generated a flood of online complaints and Microsoft has only just admitted there's a problem.
The tool relates to battery life, with people getting warnings either that the power is exhausted or worse that the battery needs to be replaced.
So Microsoft has gone off to consult with its hardware partners - it's saying there's a problem with the BIOS. Windows 7 uses information held in the BIOS to issue the messages.
But there's still debate on a Microsoft support forum whether the problem really is with the battery or not. One user complained that after he'd had the message the battery was damaged after trying it with a different operating system.
Others have attempted to roll back to XP and claim the battery still vastly underperforms.
One user, calling himself bdoserr changed his battery in his Asus Eee PC 900 last month because he took the warning seriously. He said: "The replacement is already being reported as defective, even though it's only been through two charge cycles."
He said the machine came with Linux and he spotted to Windows 7. "Big Mistake," he said. "I am not pleased."