Re: I am a new Newbie...
I have used bootable USB installs in the past, both full and persistent. I doubt your PC has USB3.0 so a full USB install (where the USB is basically a hard-drive) would be rather slow, and a persistent boot session is limited to just a few Gigs of changes before you run out of space in the Casper-rw file. So you are really limited in what you can do with a USB.
I would go with coldraven's suggestion and just get a HD to fit it and make it a fully functional PC again. I found some that will work for you with plenty of room and good enough speed for an Ubuntu (or any Linux) install for under $25. Generic 2.5 SATA Internal Hard Drive (120 GB) Any 2.5" SATA internal drive will work for you, and you probably really don't need much more than 100 Gig if this is going to be a 100% Linux "practice" system.
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