Another thing you can try:

It seems like a stretch, but I just read about someone who was having a similar issue. Turns out their router's date and time was not set. After setting it correctly, his motherboard quit resetting his date and time. Something else to check I guess.I am very much obliged to you for taking all this trouble to solve my problem.

This morning I did the RTC RAM reset using the jumper, as instructed in the manual. I re-set only the date/time, saved and re-booted. As no passwords are used, it was LEFT blank ('no password entered' statement DISPLAYED automatically in the menu). I am keeping the power on till tomorrow for good good measure. Somewhere I read that keeping the power on for about 24 hours might do the trick. I don't know whether this is true, but it is worth a try. I will check the results tomorrow and post here.

The PSU check has to be DEFERRED till then. I have no router. This is a plain home computer.

Thank you very much,
Best regards.

Oh, is the computer not connected to the internet at all?Sometimes I get confused with the internet terminology. I thought you meant a computer network when you said 'router'. If you meant wireless modem to connect to the internet - certainly yes. I am always connected whenever I use the computer.Problem solved. I erased the RTC RAM again, using the jumper. At first it didn't work. I kept setting the the date/time over again. After the third time, the battery started SAVING it and the computer is now booting normally.

I am glad I didn't try the BIOS update. Thank you for the help.

Best regards.Good to hear!