Eliminating all private keys records from pc
What you describe has some risks:


The new PC and router likely won't have the latest software updates, which could increase the chance of it being compromised immediately
The bitaddress.org website may have been compromised, in which case it may generate pre-determined addresses that are monitored for stealing coins deposited to them. This is a real and significant risk that you should take steps to avoid.


I suggest that you look at a process like this:


Download a copy of the bitaddress.org page and store it on USB.
Open it from a cleanly booted offline PC, perhaps from a live linux CD, or even better, from a permanently offline PC.
Verify the bitaddress.org code (I'm not going to cover this here; it would make a good separate question perhaps)
Generate your private keys