Brand new MacBook - Migration Assistant and now no internet

Took myself through the process of setting up a brand new macbook air today. It asked me after turning on and selecting my language and country if i wanted to set it up with content from an old mac, time machine back up, etc. I selected yes. Then I set up migration assistant on my old macbook air, and the two computers found one another, and transfer began (wirelessly). It got hung up at "less than 1 minute remaining" so i had to force shut down the new computer, it wouldn't shut down using the standard apple-shutdown. OK so i decide to backup old computer to external and set up new computer from time machine backup. New computer, however, couldn't "find" the external. maybe because it has a Western Digital lock thing where you have to enter a password to put it on a new computer? who knows. Tried migration assistant again and it worked! yea.

Now even though my wifi "pie" has all its bars and even though all other computers in my house get online wifi properly, i can't get any web pages to load. Network diagnostics tells me "we can't find anything wrong". We unplugged and replugged in wireless router, etc. Don't really know if wifi worked on this computer to begin with, or if migration assistant process screwed it up. Went in and made sure that the TCP/IP page under networks settings on new computer had all the same stuff listed as on the computers that DO get on the internet, and it did. I went into preferred networks and deleted a ton of ones that had migrated over from old computer (hotels id been in, in-laws house, etc) and moved my house up to number 1 on the list. Also tried going into keychain access and deleting the passwords for my wifi network so i could relog in… didn't help still can't get online. thoughts?

ALSO CAN YOU UNDO A MIGRATION? get it back to factory settings?