Possible? I haven't done it, but I believe so.
(A detail: you'd ordinarily want a DVD burner - the X86 .iso is about 2GB in size, and the X64 one is 3GB.)
Download and extract the iso. I think that you can run the installer from a second hard drive, a separate partition on the same drive as your current OS, or a bootable USB flash drive. (The bootable USB flash drive is most easily created by using a downloadable utility from HP. You'll find it on a Web search easily.) I'm not sure exactly how it would proceed from a non-bootable partition, but I believe that it can be done.
How did you install 7057 without a DVD drive? If you have only a DVD-ROM drive, have someone else create a DVD for the RC build, 7100, for you. It's legitimate.