Tiggy, the time and cpu clock etc. are all known and constant variables, let's go with the system clock, the seed is 9am on the 1st June 2014, you can (if you know the seed date) know what the 1,000,000,000th number is, it isn't random, it has an end result which can be known, there is a 0% chance that you *know* if a coin is going to be heads or tails next toss, it's true random.

A computer on it's own cannot generate a true random number, all it can do is apply fancy mathematics to simulate a large enough pool of numbers to suggest randomness, if the same seed is used again, the same results are shown, so the seed itself has to be randomly generated from a method that cannot be guessed so that the same results can never occur, we could go for, number of transactions currently hitting the database, multiplied by the number of people logged in, divided by the current time (UTC), again, not true random, the seed has the possibility of reoccurring which would bring exactly the same results again.

See, you're trying to make a computer generate a seed, but a computer cannot generate a random seed, but as a computer cannot generate a random number it cannot generate a random seed for the pseudorandom. If the seed repeats, the sequence repeats which is why a computer will never be able to do random because math.