there are plently of users here that have done what your trying to to do. VB can easily do what you're trying to do. the trick to it is getting from vb through windows to the pc hardware. i'm still learning but thus far it appears like

initialize serial port
open port
read / write port
repeat
when done close port

of course the syntax is everything. i saw an example on this forum not long ago, so keep digging. i have seen a number of users use hyperterminal to do a quick test of their hardware. i was searching for temperature related projects but there are endless other types too.

i've switched from VB to delphi, so i think i'll find fewer examples to help me here. good luck, stuggle on and succeed!