How can I tell if my ISP modem/router has been hacked into and loaded with any malware ?

? the question you ask implicates an answer that may be quite tech so please advise before i start unloading tips. How computer savvvy you are or else my info may be sounding chinese to you.
First of all see that you can get into the router's admin page and check the various settings to see if no devices unknown to you are in there.  Are you worried that a) someone may be piggybacking on your modem to get free internet or are you b) suspicious that someone may be attempting to or already has hacked into your machine?
 
Need a lot more info before i can PM you with details
Lastly what ISP are you using. Perhaps there's someone around here in this community that has experience with your ISP so we can give you additional info.
 
Cheers,
Edwin

Hello Edwin,
Thanks for your input, I'll try that and see what the settings are.
I am not expert at this, and there's no rush here for me,
so I'll try a few checks and see what happens.
Thanks again to you and the community, very helpful.
Ged

Just to add unplug for 5 to 10 minutes then plug it in Change your Wi-Fi Password if your are using a secured Wi-Fi as well the modem/router password then and you should be good to go. I have mine set to WPA2-PSK (AES) and see here for more info: http://www.howtogeek.com/204697/wi-fi-security-should-you-use-wpa2-aes-wpa2-tkip-or-both/
 
Thanks,
 
Daniel 😉