Don't ever remember seeing a BIOS "go kaput" unless it was being phlashed. I'd suggest removing the AC adapter then the battery. The 550 has a large access panel on the back that'd need to be removed. Right below the RAM you'll see a plug that'd need to be disconnected. After that press and hold the power button for 30 seconds. I have OCD so I always wait a minute or two then do that again. Reconnect the plug, reinstall the battery and connect the AC adapter. To the right of the power button is the NOVO button. Press that and it "should" bring you into BIOS