BIG PROBLEM :(

[Andrea_1971]

Hi everyone,
I have a problem that has been bothering me for months.
When I turn on the power strip, the PC LED lights up (steady) but the PC remains off. When I press the power button, the PC starts up regularly but stops at the "cmos date/time not set" screen and to continue with the start-up I am forced to press F1. Once the start-up is complete, the date and time are not updated.
All subsequent restarts or subsequent shutdowns and restarts performed with the power strip on (without turning it off) occur regularly.
I have performed the following tests:
- replacement of the buffer battery;
- clean buffer battery contacts on the MO;
- replacement of RAM;
- BIOS setting with default values;
- change of power strip;
- PC plug directly into the electrical outlet.
The anomaly remains and the PC, during activities, does not present any further anomaly.
Does anyone have any advice for me?
Thank you all and have a good day.
The PC is a Packard Bell Imedia 3800.
Can anyone provide me with a BIOS update?
Thanks all.

Andrea