Comebacks are funny things. Sometimes you get an Elvis 68 Special or, more recently, Prince doing guerrilla gigs in London. Other times you get Axl Rose, full of pies. So we've got good news for anyone who feared this year's Microsoft Build conference would be more Axl than awesome: the Microsoft we've seen this week is fighting fit and wearing its skinniest trousers.

We should have known, because last week's launch of Office for iPad showed how new boss Satya Nadella is already changing the company: Microsoft wants to be awesome on everything, whether it runs Windows or not.

That doesn't mean Microsoft is giving up on Windows, of course - and this week we saw the latest moves to undo the damage of the original Windows 8 launch. Build delegates were treated to details of Windows 8.1 Update 1 - Nadella's new broom clearly hasn't reached whoever names Microsoft's products yet - which runs on more modest hardware, boots directly to the desktop, and should be less annoying for desktop and laptop users. It isn't perfect, but it's an awful lot better. If Microsoft had shipped it rather than Windows 8.0, the world might be a happier place.

Microsoft's vision is of a single ecosystem across all kinds of devices, and we saw more of that this week: DirectX 12 graphics and Windows apps are coming to the Xbox One, and the latest Kinect is coming to Windows.

For our money the most interesting new technology was Windows Phone 8.1, which introduces Cortana. Cortana, named after the Halo character, is a very impressive virtual personal assistant that's a kind of cross between Siri and Google Now. As Michael Rougeau explains, Cortana will be a beta at first but "Microsoft plans to unleash the full version in the US, the UK and China in the second half of 2014."

Windows Phone has a new flagship too: the Nokia Lumia 930. Michelle Fitzsimmons has the specs: "It's packing Windows Phone 8.1, of course, and features a 5-inch Full HD display. The PureView camera rings in at 20MP. It features optical image stabilization and Zeiss optics. An HD 1.2MP wide-angle camera is affixed to the front."

Fitzimmons also has the skinny on Windows Phone 8.1. The new Action Center lets users get notifications from any app and personalisation is a key theme. There are new apps too, including Skype, Calendar and a clever new keyboard called Word Flow - it's rather like Swype and holds a world record for typing speed. It's all looking great and will roll out in the next few months.

Dub dub

Microsoft's not the only one with new phone software on the cards: Apple announced the dates for WWDC 2014 to cries of "iOS 8! Mavericks 2! iPhones and iPads and iWatch!" - tune in on June 2 for the official news.

Another giant had new toys to talk about this week, too: Amazon. There isn't a pie Bezos's blockbuster business doesn't want its fingers in, and the latest pie it wants is streaming TV.

The new Amazon Fire TV is coming for Chromecast and taking aim at Apple TV. "It's elegant, powerful and scary for the competition," Scott Alexander says. It's more powerful than its competitors, it has a massive selection of content - not just Amazon Instant Video, but also Netflix, Hulu Plus and, soon, streaming music - and it's a games console too.

Amazon has clearly been studying the competition.

"Almost every aspect of the Fire TV improving or refines the aspects of the Roku, Apple TV and Chromecast that currently vex consumers," Alexander says.

"Roku, Apple and Google are all probably feeling a little nervous today, and with good reason. Jeff Bezos doesn't like to compete, he likes to dominate. And this box has the potential to do just that." For now it's US-only, but as Amazon put it: "We're a global company with global ambitions, so stay tuned."