About two weeks ago I built a new computer with an OEM System Builders
version of Vista Home Premium.  I entered the CD Key and it worked perfectly,
for two weeks.  When I logged into my account this time it said that due to a
hardware change, I needed to re-enter my product Key.  When I do this, it
tells me that my product key is already in use.  I am going to try calling in
the verification process tomorrow but I wanted to see if there was a simple
solution that I was overlooking or if anyone else had this same problem.  
Thanks in advance.