All products eventually approach "if you use this product for anything at all, it voids the warranty". How fast they get there is an indication of the integrety (and managerial health) of the company behind them.
In my country (Norway) we are already protected better by law than the warranty in most cases, so what producers say will void it is often meaningless.
If Dell said VLC was installed so warranty is void, I'd say I want the computer fixed as a "reklamasjon"-case, and so they can't hide between stupid rules like this. This also means that we are allowed to swap RAM, CPU's etc. in our computers without fear of not getting the computer fixed if it later breaks down for unrelated reasons.
