The new TV ad, created by Crispin Porter + Bogusky in the US, features Cheryl and her husband, who want to purchase a new PC.
When Cheryl leaves the house, the Windows 7 team help the husband create a PC store in their living room, displaying all the devices available.
When Cheryl returns to the "surprise" personal shopping experience she opts for a Sony Vaio Y.
The 30-second spot, produced by Smuggler, breaks tonight on Channel 4 during 'The Simpsons' and is scheduled to run through August and September.
The campaign is supported by print activity running in titles including The Times, The Guardian and Metro, with online ads running until September.
Leila Martine from Microsoft commented: "With this campaign we wanted to convey the breadth and depth of Windows 7 PCs to suit any passion or lifestyle.
"By addressing, head on, the apprehension and confusion often associated with buying a new PC, and really bringing to life the magic that can be done with them, we want to reignite the excitement people feel for their PC."
The lead creative on the campaign is Rob Reilly, worldwide chief creative officer at Crispin Porter + Bogusky.
In June, Microsoft unveiled an interactive ad platform for the Kinect 360, which it claims will transform TV advertising into a service controlled by voice and gesture commands.