My sister's PC was infected by some adware or spyware last night, seems related to mmsassist or something like that, it will hijack the system and randomly open Internet explorer to go to some website in mainland.
I found the infected files but once I deleted them, they will simply regenerated by some process, even in safe mode.
Tried until 1:00 am last night and cannot find good method to remove it. I decided to reinstall Windows tonight.
Link to information about mmsassist: