Is it possible to install an OS via. an Android phone being used as USB?

I am building a new PC. I'm steering away from buying an optical drive with it because I know I'd have no use for it other than to install an OS.

I know its possible to install an OS via. USB, but I have some dilemmas.

1. I don't have a 4GB USB stick to use
2. Even if I did have a USB stick to use, I pretty much have no computer to use at all except for my smartphone, which I'm typing this thread on.
3. I have Windows 7 purchased already, but no other PC to use to extract files from the CD onto the USB drive (which I don't even have). But I do have a product key.

What I can do is possibly torrent (on my phone) .iso files of the Windows CD.

I was wondering, would it be possible to use my Android phone as a USB to install an OS onto my new PC the same as one would use regular USB stick?

Thanks in advance.