According to the support page at http://www.sonycreativesoftware.com and referring to the Sony Creative Software End User License Agreement, there is no restriction for installing or re-installing the software on multiple computers.
Unlike Adobe Premiere, there is no need to de-activate or de-authorize your software when you are installing on a new computer.
That means you can have the software installed on more than one computer (a home PC, a work PC, and a portable laptop) for the convenience of being able to work on projects at different locations.
However you CANNOT use the Software on more than one computer at a time without purchasing additional licenses.
If multiple, simultaneous use is needed, then you require to purchase multiple licenses (for example, a classroom or a business with multiple people using the same program at one time).
With that being said and from my own experience, Sony Vegas refused to install after the fifth computer.
I upgrade my desktops and laptops regularly and have to re-install software every time. The latest being the video editing laptop Intel i7 HP Pavilion DV6.
So now I am waiting for Sony Support to resolve the issue.
Resolved within 24 hours!
Sony Support Team wrote back saying that Sony Creative Software puts an activation limit per license and that I have re-activated this application on several different configurations since purchase. This is fine but they just needed to verify that the license wasn’t being shared. Everything appears to be in good order and I should be able to register online without any error.