I would suggest trying Malwarebytes to scan and see if some piece of malware is messing with your connections assuming you can get the installer on your computer via flash drive or something. Maybe something got by AVG. The symptoms sound a bit dodgy.

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After double checking for malware, maybe turn off any firewalls just to see if maybe a software firewall went rogue.

My Windows Firewall is off, and I disabled Norton, and that didn't help. I'll try Malwarebytes, though.

It's just bizarre because everything was working fine until I restarted. And I had a similar issue last week without restarted; I just woke up, and my connectivity was funky. But resetting the modem fixed that problem. So I don't know whether the two are related or not.

But resetting the modem fixed that problem. So I don't know whether the two are related or not.

I'd say not. Unless the modem has its own firewall, it should either let everything through or nothing. It really does sound like only certain ports are getting through, which would be a PC issue. I'm not an expert in this, but a virus/trojan is the only thing that comes to mind.

Do you have another computer you could try on that modem? Perhaps a friend could bring a laptop?

Do you have a router? I'm under the impression that having a router with packet forwarding offers much better security than a software firewall....

I don't have a router. I don't have another computer, but I could try the modem on a neighbor's laptop. But it doesn't sound like the modem is the problem because the computer is recognizing connectivity; something's just keeping programs from connecting.

AVG didn't find anything yesterday, but it hadn't finished installing the latest update, and everything was working. Maybe if I run it now after the potential virus is active, it'll find it?

GAH GAH MOTHERFUCKING GAH. How did this happen? Goddammit. The last major thing I downloaded was the AVG update.

uninstall AVG and try to connect.

Zonealarm (years ago) screwed with a few programs I was using to connect to the internet - selectively - and I had to bail on that.

You have Norton and AVG? Why both? You said you disabled Norton. Did you also try disabling AVG?

Does this sound familiar to anyone? Anyone have any idea what's going on and why this randomly happened and how I can fix it? Please?

Could be a DNS problem. Switching to OpenDNS temporarily would be a good way to test that theory.

uninstall AVG and try to connect.

Would disabling it be sufficient to test? I'm hesitant to uninstall it and lose my virus protection if, indeed, that's what's going on. Although, given that the last thing that happened was an AVG update, it does seem plausible that AVG has gone haywire for some reason...yet, why would it block ITSELF from connecting?

Zonealarm (years ago) screwed with a few programs I was using to connect to the internet - selectively - and I had to bail on that.

Weird. What the hell, AVG? Can I not use you anymore or something?

You have Norton and AVG? Why both? You said you disabled Norton. Did you also try disabling AVG?

Norton came preinstalled on my computer, but I didn't pay for the updates, so right now I just have it for the Security or whatever. And I know it's a bitch to get off my computer. I did not try disabling AVG; I'll try that as well. Maybe if I disable it, it will allow itself to finish the update and stop being a bitch?

Could be a DNS problem. Switching to OpenDNS temporarily would be a good way to test that theory.

I tried flushdns followed by registerdns. Would that resolve a DNS problem? Because it didn't work.

norton has been known to cause problems. this is a fact. you sure norton is disabled?

I might - if I were in your shoes - remove AVG altogether, test the connect, then reinstall from a new download.