Узнать некоторые временные характеристики процесса можно через:
BOOL GetProcessTimes(

HANDLE hProcess, // specifies the process of interest
LPFILETIME lpCreationTime, // when the process was created
LPFILETIME lpExitTime, // when the process exited
LPFILETIME lpKernelTime, // time the process has spent in kernel mode
LPFILETIME lpUserTime // time the process has spent in user mode
);