Update manager problem
 

An error occurred

The following details are provided:

W: GPG error: http://repo.steampowered.com precise Release: The following signatures were invalid: BADSIG F24AEA9FB05498B7 Valve Corporation <linux@steampowered.com>

okey what I do now?
I have linux mint 15

Hi there,

you didn't supply enough information to be sure, but I guess you manually added steampowered.com (whoever that is) to your software sources in order to install software they offer. And now it looks like they don't have a valid signature file.

This may be meaningless, they might just not have bothered to supply a signature at all.
But it could also mean their software download server has been tampered with.
What this means for you depends on how much you trust these people.

[X] Doc CPU

Hi. I just put your error message into a search engine and got various results that I guess would probably help. Look e.g. at this site

As a general rule when you get an error message it's always good to use your favorite search engine to see if others had the same issue before you