Hi Paddy-ARW,
Sorry for the inconvenience caused to you and thank you for your valuable question please, I would suggest you to see the below mentioned thread and see the solution provided by User6 and see if it helps, if the issue persists kindly do let me know, waiting for your kind response please.
https://forums.lenovo.com/t5/ThinkPad-T400-T500...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Please let me know, if that helps and feel free to ask back any question.
Kind Regards:
Yasir