YOU MUST OWN a valid, qualifying OS for the Computer you are using the upgrade win 7 on, just does not have to be on SSD else it is illegal.
Since you do not have an INSTALLED OS you must select custom instal and DO NOT enter your key when prompted to.
Quote from Maximum PC:
http://www.maximumpc.com/article/howtos/how_use_your_windows_7_upgrade_disk_fresh_pc?page=0,1
(1) A true geek has never been intimidated by the registry, but lets face it, it's a mess in there. To access the registry you will first need to open up the start menu and type "regedit" into the search field, followed by enter. To find the proverbial needle in this haystack, you will need to navigate through the tabs listed on the left in the following order:
HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/ . If you don't like doing it the hard way just click Edit then Find and type MediaBootInstall into the search field, and press enter.
Once found, double click MediaBootInstall and change the "1" to a "0". Once you have finished this, simply click Ok and close out the Registry Editor.
(2) Before we try to activate our copy of Windows, we need to reset or "Re-Arm" the activation sequence. To do this, simply open up the start menu and type cmd but instead of just pressing enter, you need to press "Ctrl" + "Shift" + "Enter" to run it as an administrator. You can also accomplish this by clicking the start menu, typing cmd into the search box, then right clicking the command prompt application and selecting Run as administrator.
Once the command prompt appears type slmgr /rearm and press enter. Next simply type Exit and hit enter again, after which it will ask you to restart your machine.
End quote:
With in the 30 days you must activate, at this time ENTER your Windows 7 key.