Whats wrong with my computer - Runescape disconnecting

Hey so i have a problem with the main computer.
The main computer where my modem is connected too when ever i play runescape on it in the browser or through the client it constantly signs me out every so often (within 5-10mins of being ingame) or im getting disconnected.
But when i use the computer in my room or my laptop or someone elses laptop through wifi i can play rs with a breeze without any problems and no disconnections. This only started happening when i changed our Internet service provider.
Done all my security virus malware scans and everythings all in the clear.
Just wondering if anyone would know what could be the problem any advice be good.

 

Maybe a ethernet issue in the modem. Does the main pc have wifi? Try that if so.

If not, then look for any kind of network software and disable it. Firewalls, net limiters, antiviruses, these kinds of software.

 

Its def something wrong with the modem. Connected the computer via wifi and ive been logged in to rs for a couple hours now and never signed out.

Would that mean id need a new modem or something.

 

It could still be a firewall issue. Connect the laptop via ethernet and see if the laptop has issues. If it does then it's a modem issue.