Thanks for the reply.
1) I have no USB stick/pen. I thought I had one. Turns out it's just an adapter. And my new air I got this week doesn't have any stick either.
2) When I go to mac app store and try to upgrade to Yosemite, I am prompted to enter my APPLE ID and password. Then there is an error state 'this device or computer could not be verified. Contact support for assistance'
Any other suggestions?
I did what you said and....now I have no access to the internet - no networks are showing and therefore, I cannot access the store to get the upgrade.
Installing Yosemite now on the mac book air and then hoping for a factory setting reset afterwards! Command R at reboot yes?
Marvin! I got Yosemite downloaded and clocked install. Got all the way to 'install' and then nothing happened. Nothing is installing. Arg!!!