Why does my internet keep disconnecting?

Hello,
I just formatted my pc because i had a virus and it is now back in it’s original status. The cable guy was here a week ago and installed a 32.000 internet. I am connected to the internet via cable that inputs the internet into our electrical network and from there i can directly get it to my computer from the socket one floor below the router(my room).
before the cable guy was here and before my pc was formatted(before virus[and with 2.000 internet])i had a good sustained internet connection, but now i can’t even watch a normal stream without it cutting off or i can’t even finish 2–3 mins of an online ego shooter because every couple mins or so my internet breaks off and i get kicked!!?? please someone help me fix this problem.