Okay, I'm at a loss as to what to do. I was trying to set up a bootable USB using "UNetBootin" and I didn't properly check where my stuff was actually installing to, so instead of installing to the external drive I was planning to use everything started to install to my 4 TB eHDD. Thankfully, nothing was lost... however, every single file that was added I am unable to delete through normal means. I keep getting an error every time I try to delete one of these folders that says "Error removing file /media/(myname)/My Passport/boot/en-us: Permission denied". Checking properties, I found that these files belonged to "root" and that I can't do anything because I'm not the owner.
I've tried opening a terminal so I could rm -rf these stubborn files, but I can't even access my eHDD with it. Typing that directory into the terminal gives me the error "bash: cd: too many arguments". Same thing happens when dragging the folder into the Terminal.
(If it's worth anything, I was trying to set up a Windows 10 bootable USB in case I ever wanted/needed to switch back.)