Windows 7: Error 1935 - can't install programs on Win7/64/i7 machine

I can no longer install any programs on my Windows 7/64 PC. Each time I try, I get an error message 1935 as seen in the attachment below.

Programs I've tried to install include Dragon Naturally Speaking 11.5 (the first one to get the 1935 error), Office 2010 starter edition and LibreOffice. All provide the same error. The attached message came from an Office 2010 attempt.

I have tried:

• Turning off the firewall and Security Essentials first;
• Installing from Safe Mode;
• Reinstalling .net 1.1;

and nothing works.

System: Windows 7/ i7/ 8mb RAM/ 1tb HD with plenty of room /Windows firewall /Security Essentials AV / MyBook WD network backup.



Curiously, the error message refers to "processor Architecture="amd64", but this is an intel i7 machine.

Any help is greatly appreciated.

EdB