hao123.com is a browser hijacker. Once installed, it will change you homepage to itself. To remove hao123.com use AdwCleaner + JRT + Malwarebytes Anti-malware. These apps are free. Links below:
AdwCleaner by Xplode from http://www.myantispyware.com/download/adwcleaner
JRT (Junkware Removal Tool) http://www.myantispyware.com/download/jrt
MalwareBytes Anti-Malware from http://www.myantispyware.com/download/malwarebytes-anti-malware