Glad you got it sorted

Or you can use this Free Online .DAT file converter.
Convert files from and to DAT format online - AnyConv

See if there is any help here
Get community support | Thunderbird Help

If not post in this forum for better results

Open the Read Me file in your Zip file,. and make sure you are following the first 4 steps.
That the files have been extracted to the Root of the of the drive (ie) C:\ and you are running the...

You can also download VLC Player which plays just about any Media Files, including DVD files without having to download any Codecs.

The CMOS battery would not have been the problem. The Bios could have changed from a improper shut down or an Update
Glad you got it sorted,

We don't suggest using OneDrive, but if you want to...

You cannot move a OneDrive folder like Documents to another drive.
You can move the C:\Users\UserName folders to the D: drive, As stated above

But To add to what is being said.
On the D:\Drive,...

First see if this helps: https://learn.microsoft.com/en-us/troubleshoot/windows-client/performance/event-id-41-restart

Also, try running in a Clean Boot. If this works, you can keep it this way,...

Now that the Partition scheme is correct for Disk #2 put it back in the troubled computer and try to boot to it.
If that is successful, you can start a Command Prompt as Admin and run
SFC /scannow...

The SFC command is run in Offline Mode and is correct it is Not Wrong, if you are in the Windows Recovery Environment. And you are not in Windows and booting to the Troubleshooting menu.

If you...

Since your USB Flash Drive is working, there is no problem with your USB Ports.

You say you are using a USB mouse, but then you say you tried a Wired mouse? Is this USB I presume? Does this mean...

The picture in Post #6 shows Disk 3 which includes the G:\System drive, shows incorrect Hidden Partitions for a GPT Initialized drive. (ie) no 100MB FAT32 EFI partition.
However the latest picture...

When your finger accidentally slips, it can move a file into another nearby folder, it has not vanished. this is Human Error.
As stated, if you accidentally deleted it, it would be in the Recycle...

You have to check the Health of the Drive, it may be starting to fail. As stated, you can download Crystal Disk Info and/or DiskGenius in my signature. View the SMART Info, if the Health is any less...

In the Recovery Environment, the command for SFC is different then those that are run within Windows.
As stated, you would only run these commands if the Drive was healthy. It sounds like the drive...

Glad to see you got it sorted.

What does the error say?
Is it for all 365 apps? Or just one?
https://support.microsoft.com/en-us/office/about-the-microsoft-support-and-recovery-assistant-e90bb691-c2a7-4697-a94f-88836856c72f
...

You are most Welcome!

Add Take Ownership to the Right click Context menu, then right click the Text file and Take Ownership of it.
Add Take Ownership to Context Menu in Windows 10

Go t search and type Power Options and press enter. Go to Change Advanced Power Settings, see if there are any settings for Shutting down , sleeping, or hibernating.
Go to Task Scheduler and see if...

94% rating is OK, but it just means that the drive is starting to age and is eventually going to Fail.
I would Backup your files, and make plans to replace the drive when you have time to do so

Scroll down to Standard Edition. Download the Zip File, Extract it to a Folder and run Setup.exe.

Your Windows Login Profile may becoming corrupted.
First, backup all of your personal User Files to another drive, like a USB HDD.

Disconnect any external USB HDD's and or Flash Drives
Then, run...

Backup and Recovery (W7) is no longer supported. At some point, you will not be able to restore your backup.
Again, anytime you feel the tutorials are too complicated, post the point where you got...

Try a different keyboard.
Or use the On Screen Keyboard to test.