X61 0160 low battery error

[book193]

When I tried to power-up the Thinkpad X61 (Windows 10 Pro, latest upgrade installed), it wouldn't turn on. I then disconnected everything including the battery and it did, I then re-installing the battery. I have a vague sense that I bought a new after-market battery and it is currently charged at 100%. I use this machine hooked up to a monitor and continually plugged in. I've had several older Thinkpads that I've bought on Ebay, liking them for their sturdiness and keyboard and never having had a problem before. This is the first time that this problem occurred. When I Googled the problem, Lenovo related it to the need for a bios upgrade, stating this occurred with the E-model machines and others. My machine's bios is older than the one offered. I can do this but am uneasy, fearing to brick the machine, the instructions seeming a bit complicated (at least for me). For security, I have the hard-drive log-on encryption set such that a password must be entered before the regular Windows log-on password, if this is relevant.
Question: Should I wait and do nothing since the problem may never reoccur, or do the bios upgrade? Thanks to all.

[RealBlackStuff]

Since it's an X61, you should update with Middleton's BIOS.
It puts in Slic, gives SATA-II speed, removes the wifi whitelist, and a few other goodies.
Included in the download is an .ISO file with which you can make a self-booting CD, using e.g. ImgBurn.
Before you update, remove all passwords in BIOS and set Config/Network/Flash over LAN to ENABLED.
You must also have a working battery.
http://ali.dj/blog/sata-ii-support-for- ... 61-x61-r61

M's BIOS has been applied thousands of times, no worries there.

As for your battery problems: ONLY use genuine IBM/Lenovo batteries.
Most aftermarket ones (usually Chinese knock-offs) are turning bad on you sooner rather than later.