Are you using blackpoint or blackpearl?  If its blackpoint I wouldn't expect the K2 object browser to be available in VS2010 since K2 blackpoint only supports the K2 Studio Designer.

If you are using K2 blackpearl the K2 object browser should be under the view menu along with K2 Process Management.  Since its not I would rerun setup on your client machine and make sure that K2 for VS 2010 is selected.  Even if it is you may want to unselect it and then rerun and select it again as maybe the settings weren't updated correctly in VS2010.

Hi There,
Thanks for the reply. i reinstalled and now i see it. i wonder what happened there. 

Thanks again,