Problem connecting to router (EXPERT level problem)

Factual Questions
1

My son’s laptop can no longer connect to our router. He is running Windows 7 on an HP Pavilion g4. The error message when Windows tries (and fails) to resolve the problem is “Wireless Network Connection” doesn’t have a valid IP configuration. Looking around the internet, there are a lot of people with this problem, and it’s been around for years, and only a few where it’s been resolved. I’ve tried several solutions to no avail.

If I run ipconfig /all from the command line, a lot of information comes back. One relevant line is:
Autoconfiguration IPv4 address: 169.254.115.172 (prefferred)
where the 169 indicates some kind of DHCP problem. I’ve tried manually setting the IP address to 192.168.1.1xx, for several values of xx, to no avail. I can post the whole result, if needed. I’d need to boot his laptop into safe mode (see below).

A bunch of information:
Another son has the identical laptop, with no problem.
My son’s laptop used to connect without any problem. this began Sunday.
No one else has a problem connecting on their own laptops.
I can’t connect from my account (on his laptop) either.
There is an unsecured router nearby. He can not connect to that either.
I tried connecting by ethernet cable, and get basically the same error.
If the laptop boots into Safe Mode, it can connect without any problem, for both me and him. It can also connect to the neighbor’s unsecured network. I didn’t test the ethernet connection, but assume that also works in Safe Mode.
I have tried restoring to a restore point from before the problem, to no avail. (There’s an error about not being able to restore a particular file (a configuration file from Avast anti-Virus software. Microsoft’s information dialog that says this doesn’t say if everything else worked, or if it had a problem with one file and immediately gave up, like it often does. Microsoft’s information dialog sucks.) (I will try an earlier restore point.)
I have tried manually setting the IP address, to no avail.
I have powered off and turned back on the router. (Anyone suggesting setting it to factory defaults needs to explain why he can’t connect to another router either, since that will be a lot of work.)

I have tried ipconfig /release followed by ipconfig /renew (I think the last command failed).
I have tried the commands in post 2 here, including trying them while in Safe Mode:

I have gone into Device Manager and deleted the Network Adapter, and let Windows find it again.
I have tried other things, I think. Hard to remember.

Anyone with any other ideas?

2

More:
My wife updated and ran MalwareBytes yesterday, and it didn’t find anything.
I just installed SpyBot Search & Destroy, updated it, and ran it, but it didn’t find anything.
I’ve tried turning off ipv6.
I’ve tried changing the “Windows can turn off this device to save power” setting for the Wireless LAN adapter.

I’m on my son’s laptop right now, in safe mode. Below is the (partially obfuscated) result of ipconfig /all (run in safe mode):

[spoiler]C:\Users\xxxxxxx>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : xxxxxxxxxxx
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Wireless LAN adapter Wireless Network Connection 2:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft Virtual WiFi Miniport Adapter
Physical Address. . . . . . . . . : AC-81-12-xx-xx-xx
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Wireless LAN adapter Wireless Network Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom 4313 802.11b/g/n
Physical Address. . . . . . . . . : AC-81-12-xx-xx-xx
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::ddc0:xxxx:xxxx:xxxxx(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.104(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Wednesday, June 27, 2012 5:49:15 PM
Lease Expires . . . . . . . . . . : Sunday, August 04, 2148 12:42:16 AM
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 229409042
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-15-03-xx-xx-xx-xx-xx-xx-xx-xx
DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Realtek PCIe FE Family Controller
Physical Address. . . . . . . . . : 98-4B-E1-xx-xx-xx
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Reusable Microsoft 6To4 Adapter:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft 6to4 Adapter #2
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter 6TO4 Adapter:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft 6to4 Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 9:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft 6to4 Adapter #3
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Local Area Connection* 15:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{E0435180-6BFF-xxxx-xxxx-xxxxxxxxxxx}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{5477CC50-8DFE-xxxx-xxxx-xxxxxxxxxxxx}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{A574926B-0D85-xxxx-xxxx-xxxxxxxxxxxx}:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes[/spoiler]

3

From my experience, this is almost always due to a faulty network card.

Do you have a USB wifi dongle you can try the laptop with?

4

Delete all network connections
delete all wifi-drivers

re-install drivers for wifi
reconfigure network connections

If that doesn’t work; do what Blakeyrat recommends

5

I kind of doubt it’s a problem with the network card if it works in safe mode but not normal mode.

Do you know how to use msconfig to suppress startup programs? My first guess would be some startup program or other driver/service that’s interfering. By any chance, does the laptop have some crappy vendor specific “network assistant” kind of software?

6

perhaps, turn off IPv6 unless you really know you want it. (uncheck in the items for the network adapter). Turn off for all netork adapters, wired and wireless.

169.x.x.x indicates the adapter did not receive an IPv4 address from the DHCP server (the router). It’s Microsoft’s way of saying “fine, I’ll use my own address.” Of course it will not work.

7

Why does it work flawlessly when Windows boots in Safe Mode?

No. I could try swapping the wifi cards between the two laptops, though.

Can you give more detailed instructions for this? I deleted the adapter in Device Manager, and the drivers were re-installed.

I know how to use msconfig. I don’t know how to tell which services or startup software I should run or disable.

ETA: And I really really hate how msconfig comes up in this shitty tiny window, that can’t be made any larger.

8

Check the services and make sure Wired Autoconfig and/or WLAN Autoconfig are either running or able to start.

9

Good way to start is to disable everything and see if that works.

If it works with everything turned off, then brute force approach from there is to re-enable one by one, hopefully you can discover the culprit that way.

Sorry, can’t help with the shitty tiny window.

10

Both are set to start.

I was trying to follow this, but I don’t seem to be able to run Windows Update. Not sure if it’s because I’m in Safe Mode, something is broken. Running it in regular mode won’t help if it can’t connect.

11

Sounds like that computer has been hit with malware if Windows Update is broken.

There’s some info here about resetting the Update system, but the best resolution may involve a complete “nuke and pave” reinstallation of Windows.

12

Sigh.

Apparently, my son had selected “Block all connections” on the Comodo system tray icon. :smack:

Well, thanks for all the suggestions, anyway.

It does appear Windows Update won’t start in Safe Mode. Not sure if that’s a bug or a feature.

13

It’s a feature. Safe Mode disables all non-essential services, including Help & Support and some others that Windows Update depends on.