Connect your Ethernet cable from your modem to your computer, power the modem off/30 seconds/on and wait until it's powered up, then turn on your computer.
If you get kicked off again like that by your IPS at regular time frames (and WiFi is good), it usually means there is a problem on your end.
1: Malware
2: Excessive or exceeding monthly bandwidth allotment (it is Oct 26th)
3: Unpaid bills
4: Insecure network (others doing bad things, malware)
5: P2P files sharing, illegal device online
6: Important ISP email wating your attention for something important
7: Broken device (like a defective router) or another issue. Could be a lose wire blowing in the wind and disconnecting.
Process of elimination, calling your IPS resolves many of them, get a new router/modem, then you focus on if it's your computer, the router or lines from your house to the pole. If all that's clear, and others are reporting the same issue, then the ISP will come take a look at the wires in the neighborhood, send a tech to your house to check the lines/connections.