知道检查OS是WinNT\98\Win2000的API和在NT下写系统、用户环境变量的API的高手，请拿88分吧！

Question

GetVersion()GetEnvironmentVariable
SetEnvironmentVariable

Answer 1

http://www.codeguru.com/system/WinOS.shtml
其它同上

Answer 2

OSVERSIONINFO osvi
GetVersionEx(&osvi)
osvi.dwPlatformId = VER_PLATFORM_WIN32_WINDOWS 
//Win32 on Windows 95 or Windows 98. 
osvi.dwPlatformId = VER_PLATFORM_WIN32s
//Win32s on Windows 3.1. 
osvi.dwPlatformId = VER_PLATFORM_WIN32_NT
//Win32 on Windows NT.LPVOID GetEnvironmentStrings(VOID)
 

Answer 3

OSVERSIONINFOEX osvi;
BOOL bOsVersionInfoEx;
ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));
osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX); if(!(bOsVersionInfoEx=GetVersionEx((OSVERSIONINFO *) &osvi)))
{
osvi.dwOSVersionInfoSize=sizeof(OSVERSIONINFO);
if(!GetVersionEx((OSVERSIONINFO*) &osvi))
TRACE0("VersionInfo Not Found!");
return FALSE;
}
switch(osvi.dwPlatformId)
{
case VER_PLATFORM_WIN32_NT:
//WinNT/2000
break;
case VER_PLATFORM_WIN32_WINDOWS:
//Win95/98
break;
         case VER_PLATFORM_WIN32s:
                  //Win3.x
                  break;
}

Answer 4

环境变量相关的函数有：
CreateEnvironmentBlock
DestroyEnvironmentBlock
ExpandEnvironmentStringsForUser
等，具体用法你查MSDN吧。
我用的是Win98，没法试。