I've never used VB .net, but I'd guess the reandomisation code is:
Randomize
rnd([number])
If number is [x] Rnd generates [y]
x y
Less than zero The same number every time, using number as the seed.
Greater than zero The next random number in the sequence.
Equal to zero The most recently generated number.
Not supplied The next random number in the sequence.
Well, that's it in VB but I can't garuntee that in .net version.
Remember to use the Randomize statement before using the rnd function.