Access to corparate internet

I am working in a company where company laptop is provided to me.however,I can get LANconnection but never got connection to internet.I did get the access to internet by changing proxy settings before but I guess that has been blocked by some password or something by the corporate IT.
Please suggest what I can do to access internet as I cant even open google.com which I think is a very handy search engine:( any help is greatly appreciated!