Thinkpads Forum

Hi Everyone, I've had my T420 (Win 7 Professional 64bit) for a few years now. I use it for VCDS for VAG car diagnostics and CAD when out and about to sketch ideas. About 4 weeks ago I tried to turn it on to log some data on my car before leaving for work. It wouldn't boot wake after hibernating. BUT the green LED on the fingerprint scanner was permanently lit. I pulled the battery and the AC adaptor. It still wouldn't boot. Got to work and found some videos on YouTube showing you how to discharge the electrostatic energy built up in the machine. Tried it and it booted up after pressing the power button 10 times, and holding it down for 30secs, re-fitting the AC adaptor and ONLY fitting the battery after it had fired up.

This is starting to be a problem now. I have to leave it in Sleep mode, otherwise it won't boot. I've changed the CMOS battery. Whilst changing the battery it looks like someone had been inside the laptop before me. The CMOS battery lead/connector was ripped off the board.

The only thing i did before his fault occurred was run a lot of Windows Updates. Bad practice i know but i rarely re-boot the machine, so the error may have been caused with an update from some time ago. Please help Lenovo Gurus. Thanks.

If what you mentioned with electrostatic is correct, its very possible it breaks couple chips inside.
They are very fragile again electrostatic. But have you tried play around with memory and HDD.
I never experience exactly the same case with you, but those two are the cheapest worth a try solution. If didnt work we might go down to the main board problem.