Sept. 4 (Bloomberg) -- Microsoft Corp. is turning to comedian Jerry Seinfeld to revive its Windows operating system brand as the software maker's biggest ad campaign ever began tonight.

``The Windows brand identity has gotten a little invisible,'' said Brad Brooks, vice president for Windows consumer product marketing, in an interview. ``We want to make sure Windows goes from being invisible to something that becomes indispensable.'' Brooks declined to specify how much Microsoft, the world's largest software maker, will spend.

Early customer difficulties in using Vista, the newest Windows product, hurt the brand, along with Apple Inc.'s Mac versus PC television spots, which poke fun at Windows with claims it's slow and difficult to use. Windows sales fell short of some analysts' estimates in the quarter that ended in March and rebounded the following period.

``The Windows brand has gotten tarnished and Vista didn't help,'' said Sid Parakh, an analyst at McAdams Wright Ragen in Seattle. ``A lot of people are negative about Windows more because of what they hear than because of what they've experienced and Microsoft is absolutely trying to change that.''

The advertisements feature humorous conversations between Seinfeld and Microsoft Chairman Bill Gates. The initial spot made its debut tonight during the first National Football League game of the season.

`Future Delicious'

The first spot showed Seinfeld and Gates shopping at a discount shoe store, then leaving the store eating churros, a fried pastry. It also features the Microsoft founder adjusting his underwear and ends with the tagline ``the future delicious'' and the Windows logo. The conversation between the two will continue in future ads.

The campaign, developed by ad agency Crispin, Porter + Bogusky, will cost about $300 million, a person familiar with the situation said last month. The multiyear ad program will also publicize improvements to personal computers and the retail experience, Brooks said.

All of Microsoft's biggest PC manufacturing partners have been working with the software maker for the last nine months to make machines start up and shut down faster and to cut the number of steps to set up a computer.

Some PC makers, such as Hewlett-Packard Co. and Dell Inc. will pre-install machines with Microsoft's Windows Live Suite of Internet programs, which competes with software from Google Inc. and Yahoo! Inc.

Gurus

Microsoft will also begin hiring ``Windows gurus,'' who will be stationed inside Best Buy Co. and Circuit City Stores Inc. shops to assist customers. About 150 will be in place for this year's holiday season.

The company is also revamping its Windows.com Web site so customers can get technical assistance without the geek-speak the site currently features. For example, the site will let customers search for help based on what they want to do with their PC, rather than the speed of their machine, the size of their hard drive and how much memory it has, Brooks said. The new site will go online tonight.

The company realized it needed to connect with consumers using ``humor and a light touch,'' he said. Microsoft also needs to run a continuous campaign in order to be involved with customers all the time, he said.

``This is a mindshift for us,'' he said. ``What we have come to realize is that to be a great consumer company you need to have a continuing dialogue.''

To contact the reporter on this story: Dina Bass in Seattle at dbass2@bloomberg.net;

Last Updated: September 4, 2008 21:04 EDT