Word 2007 Can No-Longer open .DOCM files after upgrade to Windows 10

Today, I upgraded a Windows 8 system to Windows 10 Home. All seemed to work well.
NOW however, Word 2007 cannot open a .DOCM file that has an embedded Excel spreadsheet object (.XLS).
I've never seen such a thing before and I'm lost.
There's a bunch of chatter about Security and Permissions for HomeGroupUser$ but I've not succeeded in getting the logged-in user (who is a member of Administrators but not HomeUsers) to open such a file.

Does anyone have a definite fix for this issue?
It apparently started with the "upgrade" to Windows 10.
I considering upgrading to Windows 10 Pro but I wonder if that's going to help materially.

Thanks in advance...

Well, I used the Retail CD to Repair the Office Standard 2007 and it went through the motions properly.
Unfortunately, that didn't cure the problem. There's some permission on the embedded .XLS file that I can't see.
The press of time and the fact that there were only about 20-25 .DOCM files prompted me to dissect them on my own laptop using Office 2010. Worked just fine. I explained to customer how to manage the resultant .XLSX files and he's happy with it.
Otherwise, I'd love to know how to undo that labyrinth of privileges but there just wasn't time.
And no, I never trusted Microsoft's "HOMEGROUP" thingy.
Unfortunately, it would appear there are settings left over from the Windows 7 instance that the Windows 10 upgrade just doesn't handle well.
I'd be interested to know if anyone has managed a 'proper' fix for this problem but I'm moving on.

Wye

Caledon Ken said:

Did you tell client product is no longer supported and it might help to re-invest. I know no one wants to buy software but it all dies at some point.

Might also check the trust center (if it was around in 2007) as it has some restrictions that can be overridden as to what files can be opened.

Yes, but 2007 works otherwise and so that's a tough sell.
The trust center seemed a good idea but had no effect. The error message is spawned when trying to open the embedded Excel file; it complains the user lacks privilege/permission to open the file.

This PC had some HOMEGROUP security things like a Security Group and a User. I don't know how that got added.
I'm loathe to remove the user and group even though Win 10 no-longer supports HOMEGROUP.

At any rate the workaround seems to work. I opened the DOCM files with WORD 2010 and then double-clicked on the EXCEL Icon embedded therein to open the Excel Worksheet. I then saved that worksheet with a useful name and that worked.
I've never seen such files before but apparently this is a rather trivial use of the DOCM methodology so the workaround was effective.
According to the client, there were only about 20 or so files so constructed and they've all been converted.

Thanks again,
Wye