Hi Roger
There is quite a bit of stuff on the net regarding this. There are a few basic questions that need to be asked.
Is the Lenovo a new one or used.? What version is the installed windows?
These will then lead to other questions that are needed to pin down the cause.
The most common cause is that the hardrive or computer were owned by a company and the licence was installed globally. This then needs to be updated globally otherwise the activation turns itself off after a period of time, hence the message.
The global installation software can be uninstalled but then it will have to be activated using a valid licence number for that version of windows. When it ll comes down to it, why not follow the links, it'll bite you in the bum whatever way you go if there is a problem. I read on one forum there is an activation troubleshooter, I can't find it but then my laptop is valid.
All sounds very tricky - good luck...