Q: what does -sh-3.2 mean? and why cant I get into :/ root

Without more context your questions are meaningless.

Try to provide the information recommended here How to write a good question

sh-3.2$  is a /bin/sh bourne shell prompt.

So are you talking about a Terminal session, or are you in single user mode?

What account are you logged in as?

What do you expect to see?  Something like:  computername:~ username$

I think you have a command prompt, so getting to the root directory would be as simple as

    cd /

and

    pwd

will tell you what directory you are currently in.

But Frank Caggiano is correct, you really do need to give a better description of what you are seeing, where you are seeing it, what you expect, and what it is you are trying to actually do.

type the command

exit

and you'll be back to your "computername:~ username$"

IIn fact, sh-3.2 means that you are at root. Probably entered the sudo su command and is now using the super user. To return to your default user type the command: exit

There is more than one way to get into trouble

Enabling and using the "root" user in OS X - Apple Support

Not recommended if you do not know what you are doing.

the exit command should return you to the default login shell