You need a Timer:
static void Main(string[] args)
{
System.Threading.Timer timer = new System.Threading.Timer(new TimerCallback(DoSomething));
timer.Change(0L, 60000);
Console.ReadLine();
}
private static int fileNo = 1;
private static string strPath = @"D:\Temp\file";
private static void DoSomething(object state)
{
File.WriteAllText(strPath + (fileNo++).ToString() + ".txt", "The text to write");
}