Oh well linux comes with all the software you need already installed on a live cd ( Try Ubuntu or Linux Mint )
It has browsers and IM clients and IRC clients and cd burning software and music players and all that stuff already installed . You don't need to install anything ( oh well for Ubuntu you would have to search on its software center for medibuntu and let it install it)
A good guide to start with is the manual already provided with the OS
As of hardware changes, it depends . For example , I didn't even know all my hardware was compatible with linux , but it worked out of the box after installing it.
maybe providing us with some information about your pc ... what's you pc's model? would help to answer that question
Anyways , even if you wouldnt have the necessary hardware to run linux just fine ( linux supports lots of hardware ) then opening up a simple thread here and i guess you would get help to make it work