The agreement includes sponsorship of the Jingle Bell Ball.
The activity, brokered by Interpublic agency UM, will promote products such as Microsoft’s search engine Bing and Windows Phone 7 mobile apps, and will integrate MSN and Window’s Live Messenger into Global Radio presenters’ online chats.
Window 7’s sponsorship of the Jingle Bell Ball includes significant on-air and online activity in the build-up to the event, as well as branding and experiential pods to showcase products such as Hotmail and Bing at the O2 Arena during the event.
The partnership follows a similar deal last year, also set up by UM, which saw Microsoft team with Capital and Heart across a series of activities, including Windows 7 as the headline sponsor of the Jingle Bell Ball.
Paul Davies, director of marketing communications UK at Microsoft, said: "We are delighted to see some of our newest and most exciting products – along with our most well-known and trusted brands – being integrated under the Global umbrella.
"Microsoft is uniquely equipped to take how Global engages with its audiences across multiple platforms to a new level. The scale of Global’s combined UK audience is very exciting and we look forward to the creative opportunities this will provide."
In the build-up to the two-day Jingle Bell Ball, 95.8 Capital FM and Windows 7 will be asking the public to upload auditions of themselves singing and dancing, to the Capital FM website in the Windows 7 "Be A Star" competition.
The winning entrants will take part in a video remake of the Christmas classic, "Merry Christmas Everyone" by Shakin' Stevens, to be shown each day at the Jingle Bell Ball, and the winner will be asked to introduce it in front of the live audience.
Other digital activity will include a viral which will allows users to place themselves inside a video of the backstage area, showing their name on a dressing room door and walking out to a crowd chanting their name.
Amanda Burningham, ideation director at UM London, said: "This is likely to become a hugely successful media partnership. It’s another great example of how we can use our excellent relationships with media owners to build broader partnerships well outside the scope of standard media."