注册表安全可写

我使用了RegSetKeySecurity设置Ｗｉｎｄｏｗｓ２０００下注册表权限，使系统键可写，不想我的想器是ＸＰ，运行后把我系统中HKEY_LOCAL_MACHINE整个键都不见了，系统瘫患了。
２０００下注册表权限在Regedit下无法设置，但在regedt32下有安全菜单项
ＸＰ下无论使用Regedit还是regedt32，都是一个样
不知那位用过这个函数？帮我看看
下面是代码：
SID_IDENTIFIER_AUTHORITY sia;
PSID pInteractiveSid=NULL;
PSID pAdministratorsSid=NULL;
SECURITY_DESCRIPTOR sd;
PACL pDacl=NULL;
DWORD dwAclSize;

CRegistry reg;

if (!AllocateAndInitializeSid(&sia,SECURITY_INTERACTIVE_RID,
0,0,0,0,0,0,0,0,&pInteractiveSid))
{

}

if (!AllocateAndInitializeSid(&sia,SECURITY_BUILTIN_DOMAIN_RID,
DOMAIN_ALIAS_RID_ADMINS,0,0,0,0,0,0,0,&pAdministratorsSid))
{
}

dwAclSize = sizeof(ACL) + 2 * ( sizeof(ACCESS_ALLOWED_ACE) - sizeof(DWORD) ) + GetLengthSid(pInteractiveSid) + GetLengthSid(pAdministratorsSid) ;

pDacl = (PACL)HeapAlloc(GetProcessHeap(), 0, dwAclSize);
if(pDacl == NULL)
{
TRACE0("pDacl=NULL");
}

if(!InitializeAcl(pDacl, dwAclSize, ACL_REVISION))
{
}

if(!AddAccessAllowedAce( pDacl, ACL_REVISION, KEY_ALL_ACCESS, pInteractiveSid))
{

}

if(!AddAccessAllowedAce( pDacl, ACL_REVISION, KEY_ALL_ACCESS, pAdministratorsSid))
{

}

if(!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION))
{

}

if(!SetSecurityDescriptorDacl(&sd, TRUE, pDacl, FALSE))
{

}

reg.Open(HKEY_LOCAL_MACHINE,"HARDWARE");

long lRetCode = RegSetKeySecurity(reg.m_hKey,(SECURITY_INFORMATION)DACL_SECURITY_INFORMATION, &sd);

return;