recognise text using ocr unavailable in adobe standard 8.1 on windows 7 PC 64bits

Before we give up completely -- what do you mean by "unavailable"? Do you mean you can't find it? That you get an error? That Acrobat crashes? That it doesn't seem to work? Something else?

Hi,

We apologize for the issue you are facing. We would like to inform you that Acrobat 8 was expired few years back.

Please try latest acrobat DC trial version https://acrobat.adobe.com/in/en/free-trial-download.html

Hope it will resolves your problem.

Feel free to contact us if you need any further help.

Thanks.

Have you checked to see if Acrobat 8 supports Windows 7?

Acrobat 8 is very old and is no longer supported.

Adobe Product Support Periods shows Acrobat 8 support from Adobe ending November 3, 2011. Acrobat 8 was not even updated to work under Windows 7. Acrobat 9 with updates is the oldest version that supports Windows 8.

You really need to upgrade your version of Acrobat.