Bill Gates tells Harvard students how he overcame his fears to launch Microsoft and make it a success

Before Microsoft became a success in the 1980s, co-founder Bill Gates struggled with self-confidence and actually feared that his business would be a bust, he told students during a Q&A at Harvard last month. "Even the idea that Microsoft would be a big company, I never would admit that to myself," Gates said.

Gates was an introvert, even, he has said, antisocial, and his original plan was to teach math. "When I was in high school I thought, 'Hey, I'm a good student and therefore I should go be like a professor of mathematics,'" Gates said. The academic discipline, Gates thought, also had "a certain purity to it," which he found alluring: Math problems, he said, "are the hardest problems to solve, and you know I like hard problems."

Until his old friend and future business partner Paul Allen convinced him to seriously pursue computer programming, Gates wasn't planning for a career in tech or business. Instead, Allen challenged him to leave his comfort zone — in more ways than one.

Although Allen didn't go to Harvard with Gates, the two worked together as computer programmers at software company Honeywell in the summer of 1974, following Gates' freshman year. When the world's first personal computer kit came out later that year, Allen suggested Gates to try something different.

"Oh, you think you're so smart, can you figure out this computer?" Gates recalled Allen telling him. "And I was like, 'Well, yes, I can.'"

After seeing the first computer with a microprocessor in person in Harvard Square, they decided "it was time to drop out and go really build Microsoft to be the first in that business," Gates said.

The decision required a serious mental shift. "So you know, that idea of being an academic to being a CEO, manager, leader type, that sort of developed over time," Gates said.

After taking the initial risk in launching Microsoft, Gates again became nervous as he watched companies he idolized fail.

"Digital Equipment (DEC) and Wang were two companies I grew up thinking those were godlike companies. Wang went bankrupt fairly early on, even though they had great innovation and later DEC essentially goes bankrupt and that was the coolest company ever and, boom, it's gone," Gates said.

As a result, Gates erred on the side of caution, and his anxieties persisted. "I always had to be careful that we wouldn't hire too many people," Gates said in an interview on "The Ellen Show" earlier this year. "I was always worried because people who worked for me were older than me and had kids, and I always thought, 'What if we don't get paid, will I be able to meet the payroll?'"

It helped when he finally learned to delegate and resist micromanaging, but that was a challenge, too: He had to force himself to stop revising and perfecting his peers' work, he told Harvard's students. "I had to say to myself, 'Ok, we're going to ship code that I didn't edit,'" he said. "And that was hard for me, but I kinda got over that."

By the time he turned 30, about six years into running Microsoft as a business, he felt "kind of stunned at what it multiplied out to," he said on "The Ellen Show."

Gates told the Harvard students that those early days taught him a vital lesson: "Things are risky. You better not miss a turn in the road."

Ultimately, Gates told students, feeling challenged early in his career helped him be successful, and working with Allen was "important in getting my mind, shaping whatever abilities I have, toward something worthwhile."

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