I have ended up with problems with ownership and permissions on my computer, probably due to a brainless recursive change of permissions..! I don't know which folder was affected, so I have changed everything back to root ownership, but realise I will never get things back to normal (even if I found a good guide in the first answer here). I now want to backup my files onto USB before I reinstall Ubuntu, but can't get to my USB ports. Have followed these instructions and it looks like Ubuntu is recognising the USB ports, so I guess it has to do with the permissions/ownership problems (as everything has gone haywire with the machine and I guess also the USB ports are affected).
I have tried running the following to find what I need to change to get things working again:
sudo find /usr -exec stat -c '%U %n' {} + | grep -v root
But I don't know what permissions/ownerships I need to change specifically to get the USB working. /media/
should be owned by root according to another machine I have, and it is, so I guess it must be something else. Any ideas? (I'm sorry to have to ask this kind of thing - I guess it is what comes from experimenting too much with too little knowledge)