Windows 7 Partial Internet Connectivity

Background: I'm running Windows 7, 64 bit, with IE9.

Symptom: Internet access works fine with everything, except any program that seems to be tied to Internet Explorer. Programs such as command line utilities (Powershell, etc.), other browsers (Chrome, etc.), FTP, Usenet reader, Tweetdeck, Dropbox, etc. all work properly. However, IE9, desktop gadgets and a couple of other programs cannot access the internet. It is like a component in IE9 (such as a driver file, a service, registry setting, or something else) is missing or mis-configured.

This all started one day when I had shut the computer down. When I restarted it, the network interface was not working at all--I could not even ping the router. I ended up having to go to Device Manager, delete the network card, have Device Manager detect it again, and reinstall it. Everything on the network came up properly but, at that point, IE and everything else tied to it (like gadgets) were no longer working.

Here is what I've done so far...

1. Looked at ipconfig /all and everything looks good.

2. HijackThis showed nothing that I did not recognize; it did complain about some common missing files, but it turns out that these entries are caused by using 64-bit Windows.

3. In addition to Windows Defender, I also run Avast antivirus. I ran a full scan in both programs and nothing bad turned up. I also downloaded a couple of others (Spybot S&D, Malwarebytes, etc.) and they did not find anything either. The only oddity is that in Avast, it complains that it cannot start the Web Shield protection, and I've even uninstalled and reinstalled Avast.

3A. I also disabled Avast, and also tried the computer with Avast uninstalled. No difference.

4. IE is not set to offline mode. (That's a common issue I've found. )

5. Ran the System File Checker--all files check out OK.

6. Looked at the Event Viewer immediately after trying to use IE, but no errors are thrown. (Unless I need to set Event Viewer to log additional events.)

7. I did a full reset of IE9, per Microsoft's instructions.

8. Just about all Windows updates have been applied, except for the past month or so that I've had this problem--I did not want to make things worse. (They are downloaded but NOT installed, in other words.)

9. I also reset Winsock using netsh winsock reset.

10. I disabled the Windows Firewall in case a corrupted entry was in the table; no luck. I do not run any other firewalls. The router has a firewall, but that has been in place for almost a year.

11. As for other things I've done, I have looked through the Local Security Policy, running services, etc., and don't really see anything out of the ordinary.

I did try this at one other Windows forum, but when I made one mention of checking registry settings, I got "talked down to". I am more of an advanced user, so I prefer to work via command line, policy settings, etc. rather than mess around with "for dummies" fixes like the other site was pushing me toward.

I have seen other complaints about this same problem, but have read through them all and none of the fixes applied, or some never were resolved.

It's a minor problem for me (I rarely use IE), but still, I'd like to have it working.

Thanks!