Internet drops every few mins while playing MMO, Streaming, etc.

internet signal drops significantly every few min while i'm doing stuff online. this happens greatly when im playing mmo, every 2~3 min, signal drops, and i lost connection sometimes, ultimately freeze then reconnects. Same thing goes for when im streaming. I've tried hard resetting my modem, router, etc and it still happens. I have chat with support, and asked them about this problems and they sent me strong signal to reset my modem. Which didnt help at all. I'd like to see what is the problem and wondering if i can fix this asap.