reboot the modem and router if you have one. Then clean your cookies and temp internet files. Reboot PC. If this dosent help, call ISP!
The internet just doesn't freeze up. Most likely, its something on the comp, like spyware, using too many resources, when using the internet.
That's exactly the problem. You need to go and buy some Draino. Then you open your computer case, and pour it in. After a few minutes you should see your internets speed kick up.
I've found battery acid, especially from a lead-acid battery to be VERY effective for this. Autozone loves whenever Comcast screws up the internet.
But yeah, unplug your modem and wait 5-10 minutes then plug. Or better get a pop-up/banner ad blocker, that'll save your internet from fritzing up. And you might want to scan your comp for spyware/malware.