If I remember, when you register VMS it registers your CPU serial number. Since I'm changing my CPU Wednesday do I have to call Sony and have them change it incase I have to reinstall?
I think you'll be fine. I had to replace my mobo about a year ago and didn't have to involve SCS. I recently reinstalled Windows on my system and just entered the SN.
That sounds right. Registration only involves the serial number and your personal information (name, email address, etc.) On the other hand, activation involves the CPU ID, but that's all automatic and can be redone without changing the registration.
So at worst all that needs to be done is the activation, which takes 10 seconds online.
There's a limited amount of registration set for you (as the rightful owner of the software) to any cpu or computer so long as you 'owned it'. If there's a problem registering you can always call in and they will extend the limited amount of times (usually 10) you can re-register after your next hard disk maintenance/reformat, or simply upgrading to a new system.