I need a new modem

Barney had a video to watch said

Cox cable company said that I need a new modem. I’ve been using this one for about 5 years and it was not connecting this morning and when Cox connected it for me, it has been running real slow.

The Cox guy said that there are no problems on my line, so that I should probably get a new modem. I know nothing about them. Please help me. I don’t know what to buy.

The only thing I run on my internet is my computer, nothing else, if that info helps.