crwdns2893792:0crwdne2893792:0 Philip Le Riche ,
This is indeed a tough one. It's obviously not even executing much or even any of the UEFI. You don't mention the RAM, but I'm sure you've tried swapping that. You say you tested with new CMOS. Did you unsolder the CMOS chip and replace it, or just replace the battery? If the former you might have disturbed soething else. And of course, you connected the CMOS battery the right way round! My best guess is that it might need the motherboard re-flowing. But any attempt to re-flow it without a propper re-flow oven is very much kill or cure, and a cure may not last. Lead-free solder is more brittle and less reliable than leaded and in disturbing the motherboard a older joint on a BGA device has fractured. Lead-free older can also grow whiskers which can cause shorts. You say you're in an organisation which I presume has a number of these T450's. The acid test would be to swap the motherboard with another, perhaps one with a different fault, like a cracked screen. Or maybe you could pick up one cheaply on eBay listed as spares or repair, which appeared to have a good motherboard. You say you replaced the trackpad. Are you sure the employee was telling you the whole story? Perhaps he spilled coffee on it and cleaned it up pretty well but nevertheless, the trackpad died. And now the motherboard has gone the same way. Any residue on it?