Weird server issue

I remember reading a book by Peter Norton about troubleshooting a ram upgrade on a PC from over ten years ago. He couldn't do one thing until he figured out a problem with another. It went on and on until he had to do around ten things before he could get it to work. I thought to myself that I could never understand computers as well as he did to figure all that out. Now it happens all the time.
That was what my Friday was like with a server we were installing. I got the call from two of our techs that a server migration from one Small Business server to another was having problems. I remoted in and found that every time we tried to make the new server a domain controller a security error popped up. DNS is almost always the problem when you make a new server the domain controller so I started there. Everything was good except for the reverse DNS lookup. After fixing that I went on to the check box for the remote delegation that is required for a server to be allowed to be a DC. We couldn't check this box because of an issue in the default domain controller policy for the DC organizational unit. I went in there and found out that the delegation right was not turned on. I changed this, and I was able to finally check the box in the properties of the server to be allowed to be upgraded to a DC.
But it still didn't work. Then I scratched my head for several minutes and just casually looked over all the stuff I already looked at. After ten minutes I noticed that although the policy I edited was now set correctly, the policy itself was disabled. I right clicked and enabled it and the upgrade went through. I left out about eight other things I tweaked because they didn't work anyway, but the point of this was to show that we start with the easy things first and work our way to the more complex. Most of the time it's something simple like DNS, but this time it was not.
Everyone says they found what they were looking for in the last place they looked. Well of course it was in the last place you looked. You just don't know which should be the first place, or the one after that. Think about that the next time you lose your car keys, again.