Earlier this week Jobs said that the PC was in decline, also an attack on Microsoft which has software on a great deal of them.
But speaking at a D: All Things Digital conference in Los Angeles the Microsoft boss Steve Ballmer said that the PC would continue to change rather than run into the sand and die out.
According to reports he also threw the gauntlet down to Jobs pointing out that it was no longer about the current technology.
"It's not about Mac and PC anymore, it will be about the thing that replaces the Mac," he said.
Ballmer told the conference that he believed Microsoft had an opportunity to also make up some ground in the smartphone market and would be working hard to make its mobile operating system more widely used.
Earlier this week Jobs had spoken at the same event arguing that Windows computers would decline in popularity as people used other means to connect to the internet, consume content and work.
Jobs was referring to the rapid spread of smartphones and other internet-connected devices, such Apple's newly-launched iPad, which he said would continue to evolve.
Jobs cited security issues, poor battery life and difficulty in use as drawbacks to the PC laptop.