Alienware is celebrating its 25th birthday . There will be a special Twitch stream later today (2pm US central time, 8pm UK time) but we already have a good idea of the headlining product from the event thanks to a press release about a new flagship desktop from the Dell-owned gaming brand. The new desktop PC Alienware wants to wow us with is a revamped Aurora system. The new design isn't very different to the one that is available currently, but looking back at the Bit-Tech archives, we haven't reviewed an Alienware Aurora since 2010, so this is markedly different to that machine. If you are familiar with the current Alienware Aurora design, the new one is rather similar but looks a bit plumper and features an optional transparent left side panel. The extra space (said to be 50 per cent greater than the Aurora R12) allows for bulkier standard hardware inside, with fewer worries about airflow.…