Best Buy gives a choice of 3 CPU models, 2 monitors, 3 printers and 2 scanners. They can operate in any combination. In other words, any CPU can be used with any monitor which works with any printer, etc. If a configuration contains 1 CPU, 1 monitor, 1 printer and 1 scanner, how many configuration are possible? What is the probability of choosing any one random configuration? If the scanner is optional, how many configurations are possible?