I had this conversation with steam support and they said i should ask that here. I dont know how can i provide more info. Here's the conversation;

Me:
I just installed the client on my ubuntu 12.04 and i get this error in terminal when i tryto open it;

"Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
libgl1-mesa-glx : Depends: libglapi-mesa (= 8.0.4-0ubuntu0.3)
E: Unable to correct problems, you have held broken packages."

Steam:
Hello Cagdas,
Thank you for contacting Steam Support.
What video card are you running on your system?

Me:
I'ts nvidia 540m. I searched around a bit and from what i understand ubuntu dont support optimus(2 gpu's on 1 system), i cant get ubuntu to recognize my second gpu(540m).

Steam:
Hello Cagdas,
Please follow the link below for information:
Title: Optimus and Steam for Linux
Link: http://support.steampowered.com/kb_article.php?ref=6316-GJKC-7437
If you have any further questions, please let us know.

Me:
Thanks for the answer. When i try to install bumblebee by typing "sudo apt-get install --no-install-recommends bumblebee linux-headers-generic" get these;

E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

What am i doing wrong?

Me:
And when i install primus from this(http://www.webupd8.org/2012/11/primus-better-performance-and-less.html) link you posted and run programs with primusrun [ANY APP] i get black screen then i have to restart the pc again.

Steam:
Hello Cagdas,
For highly technical issues it's best that you use Github to discuss them with our developers directly.
You can create a free Github account here:
https://github.com/signup/free
Once signed up and logged in you can visit our Github here and post your questions directly to our developers as they can assist with these issues better and more efficiently:
https://github.com/ValveSoftware
If you have any further questions, please let us know - we will be happy to assist you.

And im here. I'm new here so excuse the bad formatting i couldn't find how to make code blocks. Thanks in advance!