when your PC dies under Australian Consumer law we are covered by the 3 R's - refund, repair or replace, from the place of purchase.
once you buy the hardware, it is considered 'yours' to do with what you will.
if you don't like the supplied AV software, you can uninstall it and whack on your own.
need another hard drive for storage, no probs.
want more RAM, go crazy.
if the part you changed/added dies, then that obviously is that part manufacture's problem.
and of course the usual rules of 'no physical damage', 'use it as intended', 'keep away from swimming pools' still apply.
the analogy I've heard used is like your car; they can't stop you using a different octane level fuel, you can change rim sizes etc, as long as it stays safe and legal.
and it's still covered by the dealer warranty.
if your 3 year old PC (with extended warranty) dies, there would be an above average chance that within that time frame the unit has had one or more hardware changes and numerous software changes, despite this, it is still covered under the original manufacture's warranty if the broken part is theirs.
@corona, I guess the OEM term never ends, that baton just keep getting past to another manufacturer until the allotted warranty time elapses for the part in question.
PS; I'm still waiting for someone to 'define the universe' ![:)]()