I don't think so...admin is the only default username and password. Do you remember the version of previous firmware? You didn't change the login username and password before upgrade, right? Can you...

So the laptop deletes network profile automatically after your shut down the laptop? How interesting... Other wireless clients work OK except the Samsung laptop, right? Is it possible for you to...

Archer C7 V1 has no firmware to support Unifi but Archer C7 V2(Archer C7_V2_140318(Unifi & Maxis Fiber)) supports Unifi. http://www.tp-link.com.my/support/download/?model=Archer+C7&version=V2#tbl_j

How about your test in the weekend? :)

If the network is working correctly, I don't think that you need to be so sensitive... It is normal that Wi-Fi lights are flashing...

Check details here. http://www.tp-link.us/support/rma/