As Alabaster said they usually give a freebie ban, and you start getting HWID bans after your second email ban. This isn't always the case, as I've observed some people get HWID banned after the first offense, but also know people who still aren't HWID banned after their 3rd and 4th emails.
As for you cleaning your traces, you already reinstalled windows which is good, but reinstalling windows won't change your drive serials, so keep that in mind. I would advise against ever logging into the banned account again, so maybe just start fresh.
(I wrote a more detailed thread about getting around HWID bans, here:
I wouldn't be worried if I were you.