I suspect what you have on cd is an OEM version of windows.
I doubt that product key will work with a stock w7 install.
It might be easier to just get an external optical unit and then use your cd.
The CD drive of my Dell Inspiron 1521 laptop seems to have some problem which prevents me reinstall the version of Windows from the CD. As a result, I have to reinstall Windows 7 on with a bootable USB. I download a Windows 7 ISO file from the internet. During the system configuration, I am asked to enter a 25-digits of the product code in a format of xxxxx-xxxxx-xxxxx-xxxxx-xxxxx. The number on the cover of Windows 7 Professional SP1 64-bit is in a format of xx-xxxxxx-xxxxx-xxx-xxxx which isn't a 25-digit code. Why is the format not the same? And how can I use the code from the CD cover?