If I pay the $39.99 for the upgrade from Windows 7, will I still be able to use my Windows 7 license on another PC? I know it probably isn't supposed to work, but does anyone know for sure?
If you upgrade your Windows 7 license to Windows 8 then you give up your right to the Windows 7 license you upgraded until such time the Windows 8 (upgrade) license is not being used to upgrade the Windows 7 license in question.
If you "downgrade" back to Windows 7 on the same computer then your allowed to upgrade some other eligible Windows 7 license. I suggest you read the follow article over at www.zdnet.com
One of Ed Bott's Comments:
In other words you don't get to turn a single license into two because you purchase the upgrade. Its still a single license, and it can be used to upgrade any eligible license, it also can be transfered between computers and used on a single machine at a time.
Of course how exactly they will enforce their license is not clear. I suspect you could get away upgrading Windows 7 License A to Windows 8 and then install Windows 7 ( License A ) on another computer because lets face it Microsoft is unlikely to know what the Windows 7 license key was after the upgrade happens.
Edit: I provided additional clarification in my last statement.
Here is what I did in a similar case:
not sure if the policy has changed though as the last time i did it is about 2 years back when I was doing some IT support, with different windows versions.
Microsoft upgrade licences usually say
Luckily, Microsoft can't have you declared an outlaw and therefore legally have a bounty-hunter slay you and seize all your possessions. I imagine they make some efforts to make life harder for people who willfully break the terms of the licences though.