Problem Installing from USB on New BUild

I am trying to install Windows 7 home premium 64 bit from a USB stick but I have run into the following error:

A required CD/DVD drive drive is missing. If you have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.

I have tried to Google the solution to this dilemma with no avail.

The relevant specs of my newly built machine are below:

intel i5-3570k cpu
gigabyte ga z77x d3h motherboard
8 gb dd3 kingston memory
120 GB kingston hyperX 3k ssd
sapphire hd 7950 graphics card

I am attempting to install windows 7 on my SSD. This is my first home build in 6 years, and also the first time I have ever interacted with an SSD. I do have traditional a HDD, but I was told to unplug it whilst setting up the SSD to ensure that nothing was mistakenly installed onto it.

Anyways, this error, which I have listed above, is frustrating me greatly and I would really appreciate anyone's help in resolving it. I will be giving this thread a refresh every 5 or so minutes for at least the next hour so if you reply, stick around a bit I will try to respond as fast as I can.

Thanks in advance.

EDIT: I solved this problem by using my laptop to create a new image of Windows from a DVD. I had been using downloaded images, I guess these were bad files? I don't really know, but I sorted this out.