I just installed 12.04 on an external hard drive. I'm booting off a system with Windows XP on the internal hard drive. The installation appeared to go smoothly, and when I boot off the external drive Ubuntu shows up nice and shiny.
But, something is haywire with my password. The system logs me in without a problem when I use the password I thought I had assigned. However, I can't seem to do anything much in my HOME directory without prefixing with "sudo". For example, if I try to compile a C program, it will require me to prefix with my password. It doesn't have to be anything as fancy as compiling; if I just try to cp a file, I'm refsed permission until I prefix with "sudo".
Moreover, if I type "su" <cr> and type in the password, ubuntu tells me that the password can't be authenticated.
I've not had these problems in the past. Can someone point out the folly of my ways?