How do I programmatically determine if a process is running on a system?

DWORD processes[1024], processes_size, i, n;
char buffer[256];
HANDLE ph;

memset(processes, 0, 1024 * sizeof(DWORD));

FILE* fp = fopen("results.txt", "w");
if(EnumProcesses(processes, sizeof(processes), &processes_size))
	for(i=0; i<processes_size; i++) {
		if(processes[i] == 0) continue;
		ph = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, 0, processes[i]);
		n = GetModuleBaseNameA(ph, 0, buffer, sizeof(buffer));
		CloseHandle(ph);
		if(n==0) continue;
		fprintf(fp, "%d\t%d\t%s\n", i, n, buffer);
		}
fclose(fp);

DAQ_Device* Device;


DWORD DevInitProc(LPBYTE lpData) {
DAQ_Device* Dev = (DAQ_Device*) lpData;
return Dev->HardwareInit();		// returns TRUE on success
}


// In the application main window process:
case WM_CREATE: {
	//.................
	Device = new DAQ_Device(hWnd);	// The constructor just allocates memory and zeroes the variables

	DWORD dwThreadID;
	HANDLE hSSIThread = CreateThread((LPSECURITY_ATTRIBUTES) NULL, 0, (LPTHREAD_START_ROUTINE) DevInitProc, (LPVOID) Device, 0, &dwThreadID);
	if(hSSIThread == NULL) { ErrorReport(MODULE, __LINE__); return -1; }
	
	DWORD Status = WaitForSingleObject(hSSIThread, 500);
	switch (Status) {
		case WAIT_FAILED: { ErrorReport(MODULE, __LINE__); return -1; }
		case WAIT_OBJECT_0: {	// Normal thread termination
			DWORD dwExitCode;
			// What did DevInitProc() return?
			if(!GetExitCodeThread(hSSIThread, &dwExitCode)) { ErrorReport(MODULE, __LINE__); return -1; }
			if(!dwExitCode) {	// DevInitProc() returned FALSE
				MessageBox(hWnd, "Instrument not found.\nCheck the power switch.", " Attention:", MB_OK | MB_ICONEXCLAMATION);
				return -1;
				}
			if(!CloseHandle(hSSIThread)) { ErrorReport(MODULE, __LINE__); return -1; }
			break;	// DevInitProc returned TRUE, continue with WM_CREATE
			}
		case WAIT_TIMEOUT: {
			MessageBox(hWnd, "A hardware initialization problem detected.\nPlease call for instructions.", " Attention:", MB_OK | MB_ICONEXCLAMATION);
			TerminateThread(hSSIThread, 0);
			CloseHandle(hSSIThread);
			return -1;
			}
		}
	//.................
	break;
	}	// WM_CREATE