Linux Panic Mode and Ubuntu Warning

Our relatively Old PC had a SSD master and a SATA secondary disk.
SSD do not have master boot record and only boots on distribution. I have my own ways of circumventing booting problems and I managed to have Debian and Emmabantus installed in the 120GB SSD.
I somehow got everything booting on the second drive.
Thankfully no master and slave with SATA disks.
To boot I have to press F2.
Yesterday I decided to remove the SSD and put a 250GB SATA disk and installed Ubuntu and everything went OK and at the final second Ubuntu warn that the system is going to crash.
Did not give details and the computer did shutdown.

I could not boot it again and start button went dead.
Except for cleaning dust and spider webs I practically did nothing.
I did not touch the RAM.
I had a nice graphic card I had removed from another computer I dismantled.
I fixed it and closed the chassis.
After few hours I tried switching on the computer.
It was dead for no obvious reasons.
I was in panic mode by this time.
Then having slept for a while I decided to prove the CMOS.
It was dead.

Luckily I had a spare CMOS battery and fixed it and the computer booted.

I have used computers for so long this is the first time I had a dead CMOS battery.

I am back installing and installed Ubuntu successfully.