My really old Lenovo Thinkpad started insisting to reboot after shutdown a while ago, and after a hard drop that left the battery dislodged, it froze after bein

My really old Lenovo Thinkpad started insisting to reboot after shutdown a while ago, and after a hard drop that left the battery dislodged, it froze after being powered on. I had to force it to power off, but that apparently broke it, it won't light up the screen and respond to inputs despite blowing the fan. I disassembled the screen and replugged the data cable, pressed power button in various ways to no avail. I was about to give up before reading a forum post describing a similar laptop, and emptyed the RAM slots and found it beeped when powered up, so the CPU is OK. I then unplugged the battery and CMOS battery and pressed power button for a while, put RAMs and batteries back on, and it just revived. Removing RAMs made the difference, it's done if RAMs were soldered on. It happened again a few days ago after it was left with no power, and I had to do those thing again, otherwise it has no issues. I think the CMOS battery is probably dead.