Thanks mediator & Yamaraj for your help.
I actually wanted to know how can I prevent a program from accessing the Internet at all, like konqueror (I am a KDE fan). I am just curious to know that. Also how can I verify the GPG key manually?
Thanks mediator from clearing my doubts about yum. But I never install anything from my RELIANCE broadband connection (115K max) at my home. I just copy the needed packages and download them at my office (I have all that permission at my office

) from sites listed at repo files in yum.repos.d directory. I think that will not cause any problem because yum also uses the same loaction to download files from.
Also please help me installing the fingerprint theme....and consider starting a new thread which help newbies to make their system go WOW...
Thankyou.
Subrata Bera.