We need a lot more information here. Like, what internet service, what router, how are the other machines connected to the router (same or different to the problematic machine), etc.

everything was the same except a new modem and provider, smae speeds as well. on other computers the internet is fine and feels like nothing changed. but on mine is really slow.

Connection speed issues are likely from the ISP. Might want to give them a call to test the speeds.