I think I may have solved this. I tried all sorts of configuration changes, but then when I set the laptop to boot in safe mode with most drivers therefore disabled, the problem still occurred. I saw someone had mentioned the CMOS battery. I removed it, which is difficult on the E7240, it is pretty buried. But on reboot it shutdown and stayed shutdown. I checked the battery with the voltmeter and it was still holding 3 volts. So I replaced it and the laptop booted and shutdown correctly. So it seems that temporarily removing the battery fixed the problem.
Hi. Looking for advice on a strange problem that started recently. I bought a refurbished E7240 for my mother a year ago. Worked perfectly. Recently this problem appeared: On shutting down (from start menu, shutdown.exe, etc.), if the PSU is powered and plugged in, the laptop remains shutdown, as it should. But, as soon as the PSU is powered down or disconnected, the laptop boots without touching the power button. If the laptop is shutdown while only on battery, it reboots after about 10 seconds. The only way to keep it shutdown is to either leave the PSU plugged in and powered or to remove the battery within a few seconds of shutdown. Suspiciously, the power button seems to have stopped working. I've tried the following so far, but nothing helps: Apart from this, the rest of the laptop works fine. Thanks for any advice, since I'm not sure what to try next. Steve.
E7240 will not stay shutdown