Question about reusing Windows 7 product key for new desktop

Hi guys, I have a rather unique sort of situation I'd like to ask about Windows 7 and reusing a product key. As I understand it, OEM product keys cannot be reused. However, I'm not sure of my situation here.

I am planning to build a new desktop computer from the ground up, with Windows 7 as the OS.

Now I have an Acer laptop that has a failed screen that is not worth replacing since it is out of date anyway, and I'm not going to use that computer again. Here's where the puzzling thing is:

• The Acer laptop originally came with Windows Vista installed.
• I bought the laptop in 2009, during a six-month period where Windows 7 was offered as a free upgrade disc that would be sent by Acer when Windows 7 was released. (this was also offered practically every other computer manufacturer, like Dell and HP etc)
• Subsequently, I then used this disc to install Windows 7 and used the laptop with Windows 7 running until the screen failed, as mentioned before.

So my question is, would I be able to reuse the Windows 7 key on my new planned desktop? Is it still considered an OEM product key, or is it something else?

 

The keys that come with OEM hardware (ie. an Acer) can only be used on that OEM's hardware (ie. an Acer).

 

I am not completely sure about the legality issues but since you would only be using the Windows 7 OS on one computer I don't see how that could be illegal even if it isn't on the original PC.

A couple of years ago when I was playing around with Windows 7 RTM I accidently activated it on a HP laptop with a backup of my daughters ASUS certificate and OEM serial (same version) that I had saved using ABRbeta so I know that another manfacturers cert and matching OEM serial will work on a different manufacturers computer. I replaced the cert with HP's cert and OEM serial and the OS was still activated and working.