CNN - For nearly a year, television and Internet audiences have been seeing a familiar string of ads from Apple Inc. attacking rival Windows-based computers. With this week's release of Windows Vista, the newest jabs aren't any friendlier. In one ad, the character personifying the PC is dressed in hospital patient garb, talking about how he's set to undergo major surgery to upgrade to Vista. He then saunters off, telling the Mac character that if he doesn't come back, Mac can have his peripherals. In another ad, a man pretending to be the Mac character heaps praises for the PC -- until the real Mac character steps in, confounded, asking "What's going on?" The fake Mac replies, "Nothing," and then mutters "I'm a fan" as he walks away. On its own Web site, Apple Inc. tells visitors to get a Mac, stating, "Why upgrade to Vista when you can upgrade past it?"