Windows Platform SDK Download Sites:
Windows Server 2003 PSDK February 2003 Edition，可以和VC6一起使用、并支持各种目标OS的最后一个版本的SDK。
This edition of the SDK supports development for the following platforms:
Windows Server 2003
Windows Advanced Server, Limited Edition
Windows XP
Windows XP 64-bit Edition
Windows 2000
Windows NT versions 3.51 and 4.0
Windows Millennium Edition
Windows 95 and Windows 9
XPSP2 August 2004 Edition，可以在VC6使用，开发针对XPSP2的特殊功能的程序，可以和上面的一道使用，但请安装在不同目录。
Newly released: The Platform SDK for Windows XP Service Pack 2 support
(includes MDAC 2.8, Tablet 1.7 and Windows Installer 3.0)
The XPSP2 version of the Platform SDK was developed to work either side by
side with the Windows Server 2003 SDK or standalone but will not provide
build environments for:
Windows Server 2003
Windows Advanced Server, Limited Edition
Windows XP
Windows XP 64-bit Edition
Windows 2000
Windows NT versions 3.51 and 4.0
Windows Millennium Edition
Windows 95 and Windows 98
You must install The Microsoft Platform Software Development Kit (SDK) for
Windows Server 2003 for those environments.The SDKs can not be installed in
the same directory for side by side performance.
Windows Server 2003 SP1 Platform SDK Web Install，最新版的SDK，可惜不能和VC6一起协作，不再支持NT4和9X。
This edition of the SDK replaces the previous SDKs for Windows XP SP2 and Windows Server 2003 and can be used to develop applications for those platforms.
Supported Operating Systems: Windows 2000; Windows Server 2003; Windows XP 64-bit; Windows XP Professional Edition ; Windows XP Service Pack 1
This SDK does not support working with Microsoft Visual C/C 6.0 as support for VC 6.0 has ended. The last SDK that will work with VC 6.0 is the February 2003 Edition.
若你使用的是Visual C++ 2005 Express Edition，请参考：Using Visual C++ 2005 Express Edition with the Microsoft Platform SDK。
Platform SDK - Install - Home
http://www.microsoft.com/msdownload/platformsdk/sdkupdate/downlevel.htm
打开vc6,菜单tools-options-directories.增加以下路径
executable files
你的platform安装路径/bin
你的platform安装路径/bin/winnt
include file
你的platform安装路径/include
library files
你的platform安装路径/lib
source files
可添加也可不添加
配置完之后，可以调整各路径与原有路径的前后次序，因为编译和连接的时候是按照顺序寻找相应的include和lib。为了保证用上最新的，你可以把路径放在原来的配置中vc6自带的sdk路径前面。
上面只是一个配置sdk的方法，至于能否解决你的问题，只有尝试之后才知道了
最后一个支持vc6.0的sdk
http://www.microsoft.com/msdownload/platformsdk/sdkupdate/psdk-full.htm