As another one of those affected by this annoying problem I've been casually following this thread for almost a year. I see that we have now attracted the attention of Mark Lenovo, so perhaps that will provide the needed impetus for an actual solution.
If you're unlucky enough to have one of these affected T410 laptops, it is extremely easy to reproduce the problem. It occurs nearly 100% of the time if the battery is below about 15% charge while occuring maybe 5% of the time when the battery is above 50% charge. I suspect it really does have something to do with the power management software as when I changed to a different version as recommended elsewhere in this thread, the problem immediately nearly disappeared for me. Though for reasons I cannot fathom, it came back after a few weeks.
Even though my warranty is about to expire, this is not a problem I deem worthy of sending my laptop into a distant service depot for an indeterminate time for an indeterminate fix. When I plug in the A/C and the backlight goes off, I close the lid, wait for sleep mode, open it up, and scan my fingerprint. A 15 second inconvenience. I like my T410 a lot but it's unnerving to see Lenovo still unable to fix an easily reproduceable problem a year after its reported.
