.dll only works properly on Windows XP and Vista but not 7?

I have a windows .dll file (from a third-party - which have discontinued supporting it and I don't have the C sourcecode to rectify the problems).

I'm using the .dll in a project of mine.

The .dll file works perfectly fine under Windows XP/Vi开发者_运维问答sta (as it was released at the time of when these OS versions were current/latest) - the issue is now that the project is now limited to Windows XP/Vista users (due to that .dll) - when it runs under Windows 7 it slightly malfunctions (ie. produces different results then compared to Windows XP/Vista).

I believe the problem is Microsoft must have changed something (within the Windows library or something?) which is effecting the compatibility.

So I was wondering - I know its not really the best option but as a temporary/hackish workaround is their someway I can emulate Windows XP/Vista functionality for the Windows 7 users, ie. is their any projects designed for this - example => http://www.busybox.net/about.html (which allows Linux functionality to be able to be executed on Windows).

Appreciate all suggestions/workarounds.

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In Windows 7, you can run an executable in Compatibility Mode, and set it to run in a mode compatible with Windows XP. For details, see Make older programs run in this version of Windows.

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Note that, you can't force this .DLL to always use a compatibility mode, but you can change your installer to make the appropriate registry settings for the user or machine that do this.

All you need to do is add a registry key as follows. Under:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Application Compatibility\Layers

Add a key like:

"Path\To\Program\YourExecutable.exe"=WINXPSP2

This will cause your program to always run under compat mode. You can also set this in HKCU if you prefer to just set it for the current user.

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That sounds too easy: But what about Windows Compatibility Mode? Maybe it works.

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You could try running your app on Windows 7 under Windows XP Compatibility mode and compare the results to those from native Windows XP.