linux ubuntu help

[2tone]

Have installed linux ubuntu on to a system and seem to be having some probs , trying to install a file in to usr/bin it then says you cant install this some thing about access but im loged in as main user and have checked pass as well even when i go in to the term and type su in and hit enter the type pass says authentication failure . Im not sure maby it was an install problem as when i turn the system of every thing logs out then it just sits there with ubuntu wrote on the screen as if its not shutting down

[Devilfish]

Try to reset the root password...

sudo passwd

If that doesn't work, use the CD to boot into recovery mode, you should be able to set the password there.

[2tone]

tryed that so i did i think im going to do a new install some thing might have went wrong nothing wants to play

[2tone]

well think it was the hard drive i was using as when i did the new install it every thing just shut down so got a new one there and setting it up now

[2tone]

Ok this is driving me mad every time i try and put a file in usr/bin i get error permission denied it just wount let me install this file im not sure why any help with this would be great thanks

[Devilfish]

Did you not set the sudo password during the install process?

[2tone]

Did you not set the sudo password during the install process?

more than sure i did if it ask to install updates i can put pass in and it updates so im lost in what is going on here it wount even shut down when i click shut down be trying ever thing with it