some x86 programs no longer working on Windows 7 64-bit

[LMHmedchem]

Hello,

My father's laptop has Windows 7 64-bit professional installed on it. In the last year or so some programs have stopped working, even though they have worked on this OS installation for many years. When I try to start the programs I get a message that the x86 program is not compatible with the OS, though this has never been an issue before. I have tried every compatibility mode and also shut off UAC and tried run as administrator with no effect.

The message is,

"The version of this file is not compatible with the version of Windows you're running. Check your computer's system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher."

As I said, this software has run on this computer for at least 10 years. The software in question is all x86 (as far as I have found), but x86 programs have always run, otherwise why would there be an x86 program files directory.

One of the programs is Adobe Acrobat and I assumed that this was just Adobe breaking their old software when a new version was released, but then I found the same issue with Crimson editor. The desktop icons for these programs have changed in appearance as if the icon is not in the place where it is expected.

I thought that Windows 7 was no longer being updated other than security updates so I'm not sure what would have changed to cause this.

Suggestions are appreciated,

LMHmedchem