You don't create a powerful company like Microsoft just by being lucky. This is the guy who brought personal computing to the masses. This is the guy who managed to grow his company into the behemoth that it is today. This is the guy who responded to the Internet threat brilliantly (well initially that is.).
Dirty tricks are PARTS AND PARCEL of the world, especially in businesses. The techies are insulated from such behavior, which is why they are usually shocked at such behavior. People on the business side are used to such behavior. They deal with it. They counter back. Wall St revel in it. Govts use them all the time. This is society at its normal equilibrium. Google, being a techie wonderland, is trying to avoid this for as long as possible but trust me, WallSt will push their hands sooner or later.
Paul Allen wouldn't have build Microsoft into the success that it is today. He just isn't as sly as Bill is.
I would also like to know if they somehow covertly helped the BIOS reverse engineering process.
Everything they did up to Windows 3 derived from that - do whatever it takes to secure a market for their OS. They did not leave OS/2 to IBM because the codebase was bad. They needed control of the OS in order to keep it a commodity and having a competitor developing the OS that runs on commodity PCs was out of the question. Up to the launch of Windows 3, the public discourse was that OS/2 was the future. It changed dramatically at that minute.
They played dirty tricks all the time. Threatening Apple not to renew the Applesoft BASIC license was a way to secure Apple would endorse Microsoft BASIC on the Mac and ditch a competing product. I don't know what else they got from Apple while their cash cow had a piece of MS software within. It certainly made Apple's contracts better the next time.
They got lucky a couple times and IBM got fooled twice. Their dominance is the consequence of luck and borderline criminal tactics. I see no huge genius here beyond one that was willing to bend the law (and morality) as much as he could.
It's also unclear how much of this came from Ballmer.
As far as I know, the big genius among the Microsoft founders is Paul Allen.