If you have a Lenovo Flex 2 or Flex 3, you may have a situation in which the unit goes to sleep but will not power back up. Instead the power LED just keeps flashing at you.
Many people believe this is related to Windows 10 but I have read several first hand accounts from people who had the problem with Windows 8.1, so I am unconvinced. Regardless, it would appear the problem is related to power management settings.
In my case the solution was to pull the battery, wait 2 minutes and then reconnect the battery. The problem is that in a Lenovo Flex 3, that is not a simple as it sounds because the battery is internal. Fortunately, it is still not very hard to do:
- Unplug the unit from the AC power and all other devices (i.e. USB mouse…)
- Turn the unit over and remove all 10 screws
- From the corner under the screen near the network and Kensington lock port, use your fingers to pry the back off
- I have done this 4 times now, without any damage to my unit
- Disconnect the battery connector cable from the motherboard
- In my case my fingernails just would not do it, so I used a tiny ‘flat’ screwdriver to pry each end of the black plastic connector out of the metal header
- Let it sit for a few minutes (2?) so that everything on the motherboard drains.
- Slide the battery connector back into the header
- Press the power button and see what happens
- If it powers up, put the back on and screw it down, your done
- If it does not power up, disconnect the main battery again, pull the BIOS battery, let it sit for 5 minutes (to drain) then plug the unit into the AC power adaptor (i.e. do NOT reconnect either battery) and power up
- If this works, power down the unit, reconnect both batteries, put the back on and screw it down, your done
- If your Flex 3 still does not work, you likely need to put everything back the way it was, call Lenovo for warranty support and make sure you don’t tell them you pulled it appart because they might void your warranty (or buy a battery off eBay)
Source: SOLVED: Lenovo Flex 3 Flashing Power Light But Will Not Power Up – Up & Running Technologies Calgary