Acrobat Reader& Standard Compatability

Not really. You will find the products fighing to be the default program for the various Acrobat file types and web browser plug-in. Version says it can, but you will still have deuling products.

thanks for your reply !!

Are there any KB articles to support this- i know exactly that this is the problem but I have some non believers in management

You could have Adobe Reader 8 & Acrobat Standard 8 (ver 8.x) or Professional (ver 8.x) or 3D (ver. 8.x) installed on an XP SP2/SP3 or a Vista computer.Issues can arise when different versions of Acrobat/Acrobat occur.
In most cases a Reader version not the same as the Acrobat version is "acceptable" (see the version interoperability charts in the first two interoperability links below).
If Reader/Reader is attempted then the new version install will remove the older version.

In your situation, if Reader 8.1.2 is present and Standard 8.x is installed by a non-customized installer you are afforded the opportunity to select which (Reader or Acrobat) is to be the designated "Default application for viewing PDF".
Expect a similar scenerio if Acrobat Standard 8.x is already installed and you are installing Adobe Reader 8.x

A screen shot (for version 7 but applicable to version 8) of the installation dialog for selecting the default application can be viewed at this web page (6th image down).
[url]http://www.trinityra.org/IT_Support/Install_Adobe_Reader_708.htm[/url]

Some Interoperability information.
The Version interoperability charts (first two links) can be useful.

Acrobat product interoperability: Install and remove Acrobat 7.0.x (Windows)
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=326272[/url]

Acrobat product interoperability: Install and remove Acrobat and Adobe Reader (9.x on Windows)
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=333223&sliceId=2[/url]Interoperability with internet Explorer & AOL Browsers
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=333544[/url]

Interoperability with Firefox & Mozilla Browsers
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=333563[/url]

Interoperability with Safari
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=333545[/url]

Interoperability in web browsers (PDF pages not appearing)
[url]http://kb.adobe.com/selfservice/viewContent.do?externalId=328233&sliceId=2[/url]Be well...