Windows 10: restarts

I upgraded to Windows 11 In Nov. Since then, every time I upgrade and restart my computer, I lose any data files I've updated or created in the last month. This happens in every program from Excel, Outlook, Quicken, Quickbooks , etc. Any ideas?

:)

 

Inexplicable restarts

Thanks for your patient help and analysis, zbook. I'll step through some of your suggestions over the next few days - there's a lot to do and some look a bit hairy! That is, for a PC that is working sweetly right now...

Meanwhile, as requested in the BSOD thread (sorry, I misunderstood and posted there by mistake), I've attached both ZIP files.
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One step I did try right away was to answer your question about whether my BIOS is up-to-date. I had no success at the AMI site but did get some info from this commercial site:





It was one of the '9' (I counted 10) listed here:





Terry, East Grinstead, UK

 

random restarts

Hi Lili,

Hardware failure or system instability can cause the computer to
randomly restarts. As our initial troubleshooting step, we suggest you to run the Power troubleshooter on your computer and check if it fixes the issue. Here are the steps:

• Press Windows key.
• Type Troubleshoot.
• Under Find and fix other problems look for
  Power.
• Then Run the troubleshooter.

Update us with the outcome and if you need further assistance.