Some programs generate their "random" numbers based on the way a person types the input (time between each key stroke). I'm pretty sure this is true for encryption programs such as PGP or GnuPG. Seems like this is a pretty good source of randomness because as someone types in their passphrase, they probably aren't going to type at a completely consistent rate.

As far as Visual Studio goes, I'm pretty sure the clock is used for a seed for random numbers. In VB it uses the Timer variable as a default when no seed is given. This variable holds how many seconds have passed since midnight.

I agree with Negative. I don't think that anything is completely random. But there are some things that are less predictable than others.