Can't loggin as rot at boot

Hello

I am still learning Linux so I hope fols don’t too hard on me, but I was learing how to compile a tar ball, and while all seemed to go well the app was not working. I decided I would delete the files. I the porcess, I must have deleted a needed file, and the the machine locked up and I truned the power off, on reboot it had taken my whole user name (actually deleted the whole home/randy, which I know I did not do) In any event and I was able to login in as Randy and the as su get into a session. I was copying file back, but also logged in a decide to edit my “Randy” the user account, well this was a mistake, because know all I can do is see it bot up to a login prompt and I can not login at all. All I get is GDM user ‘gdm’ does not exist and the it takes me to root and ask for a login it. I don’t recall if I create a name for my su login but I am really stuck here and would appreciate any help…It’s a netbook BTW and I don’t have a CD/DVD but might be able to boot from an SD card as my BIOS recogizes it. I would however like to try and avoid that route if possible.

Thank you

If it helps any I jave just finished creating a DSL (Damm Small Linux bootable USB drive)

I am hoping I can us it to recover my system, but sure could use some help…Thank you