After getting all existential during the first two videos in its $US300 million campaign to burnish Windows’ image, Microsoft gets a lot more specific in its third.

The brand-less, existential adventures of 90s comedian Jerry Seinfeld and recently-retired founder Bill Gates over the past two weeks are replaced by a clip featuring one Sean Siller (pictured right), a Microsoft employee who bears an uncanny resemblance to the “PC Guy” in the Mac Guy vs PC Guy commercials – the wildly successful Apple campaign that Microsoft targets with its new video.

After featuring Siller saying “Hello, I’m a PC and I’ve been turned into a stereotype”, the clip goes on to feature a series of more happening Windows users who all proudly state “I’m a PC”, including Desperate Housewives’ Eva Longoria, rapper Pharrell and an Obama blogger.

Gates also pitches in with the trade-mark droll style he developed during the first two clips, with “I’m a PC user and I wear glasses”. Seinfeld, who is paid $US10 million for the campaign, is AWOL, at least temporarily.

The key message is that PC users are OK. You no longer need fear that Apple owners are hipper than you. More, the father of Windows is a friendly, self-effacing guy, not the Bad Bill we saw angrily rocking back in fourth in that notorious US Department of Justice antitrust video deposition.

And it seems to be a message that’s finally getting through. After two weeks of “WTF?” reaction, advertising commentators who’ve previewed the new commercial are giving it glowing accolades.

No doubt the industry’s positive response is helped by the fact the viral internet circulation of the first two clips will be surplanted by regular broadcast TV buys for the third (which will debut around the US version of The Office). For now it’s bye-bye Jerry, hello Sean.