#include <tlhelp32.h>

하시면 될듯...  그리고 이소스도 참고해 보세요... excel.exe 를 쥑여(^^;)줍니다.
죽이고자 하는 프로세서로 대체하시면 됩니다..

void __fastcall TForm1::KillExcel()
{
    // TODO: Add your control notification handler code here
    HINSTANCE modKERNEL = GetModuleHandle(("KERNEL32.DLL"));

    CREATESNAPSHOT pCreateToolhelp32Snapshot;
    PROCESSWALK pProcess32First;
    PROCESSWALK pProcess32Next;

    // 동적 함수 할당
    pCreateToolhelp32Snapshot = (CREATESNAPSHOT)GetProcAddress(modKERNEL, "CreateToolhelp32Snapshot");
    pProcess32First = (PROCESSWALK)GetProcAddress(modKERNEL, "Process32First");
    pProcess32Next  = (PROCESSWALK)GetProcAddress(modKERNEL, "Process32Next");

    if (    NULL == pCreateToolhelp32Snapshot    ||
        NULL == pProcess32First        ||
        NULL == pProcess32Next    )
        return;
    PROCESSENTRY32 proc;
    proc.dwSize = sizeof(proc);

    HANDLE snapshot = pCreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    /* Now that we have a snapshot of the system state, we simply
    * walk the list it represents by calling Process32First once,
    * then call Proces32Next repeatedly until we get to the end
    * of the list.
    */
    pProcess32First(snapshot, &proc);
    if( !stricmp(proc.szExeFile, "excel.exe"))
    {
        HANDLE ExcelProcess = OpenProcess(PROCESS_ALL_ACCESS, False, proc.th32ProcessID);
        TerminateProcess(ExcelProcess ,0);
        CloseHandle(ExcelProcess);

        CloseHandle(snapshot);
        return;
    }

    while ( pProcess32Next(snapshot, &proc) )
    {
        if( !stricmp(proc.szExeFile, "excel.exe"))
        {
            HANDLE ExcelProcess = OpenProcess(PROCESS_ALL_ACCESS, False, proc.th32ProcessID);
            TerminateProcess(ExcelProcess ,0);
            CloseHandle(ExcelProcess);
            break;
        }
    }

    CloseHandle(snapshot);
}
//---------------------------------------------------------------------------