1) Yes. A reset will reset all the options on your router back to factory defaults (including logon id/password as well as your all your wireless settings - including SSID and password)
2) But did you buy the Huawei Echolife HG520s yourself? I tried to take a quick look at it and i suspect it may be supported by your ISP. If so, you're best to contact your ISP about the reset as they may want you to also set special options specific to your ISP internet connection service
my neighbour suggested it to me, so we went with it, i heard that some1 had this problem to, and he started saying something about having all proxy settings off or somin, got any ideas?