Update:
1. Workaround - Reinstalled EU on the C partition. Same for a few other games. All working fine. I can play EU again
2. Ran AVG Deep Scan all drives (took hours) - no issues found.
3. Windows update applied (automatically) - issues still persisted "Windows cannot find" etc when clicking on Word, Excel, PDF files.
4. Update AVG Tuneup and ran it - issues still persisted "Windows cannot find" etc when clicking on Word, Excel, PDF files
5. As a test, reinstalled Abobe Acrobat reader - issues
still persisted "Windows cannot find" etc when clicking on Word, Excel,
PDF files
6. Started machine this morning and
suddenly I can now open Word, Excel, PDF files.
Summary:
"Seems" to be working as normal now.
I have no idea why
Thanks to all the members for their help and recommendations.