After installing Avast, my wireless connection displays the message: Limited or no connectivity. It tells me that it could not retrieve a valid IP address from the server. I know all my network settings are correct (been using them for quite some time). This has happened on my two machines: Gateway laptop, XP Pro SP2, and Alienware laptop XP Media. Even after unistalling Avast it won’t connect, but the problem doesn’t start until installing an antivirus. I have to do a system restore just to get online again. Any advice is greatly appreciated.
I don’t think this is avast releated.
I mean, the computer cannot know it’s own IP… avast does not change IP or connection settings.
Is the service DHCP running in your system (Control Panel > Administrative Tools > Services).
If you open a dos window and run
ipconfig /all
what do you see?
DHCP is running.
IPCONFIG /ALL REPORTS:
Host name: Brian
Primary DNS Suffix:
Node Type: Unkown
IP Routing Enabled: No
WINS Proxy Enabled: No
Connection Specific DNS Suffix:
Description: Orinoco Mini PCI card
Physical Address: 00-02-2D-B2-35-BD
DHCP Enabled: Yes
Autoconfig Enabled: Yes
Autoconfig IP Adress: 169.254.116.50
Subnet Mask: 255.255.0.0
Default Gateway:
Non-filled in areas are blank
You should have connection. Your IP is here…
Are you still seing te ‘Limited or no connectivity’ alert?
Yeah, I can’t get online. I can’t even access the router even though it sees it. I tried plugging the laptop right into the modem and still nothing. It gives me an IP address but it says it didnt get a valid one. I don’t understand why it does this. Technically with all the settings I should have access.
Do you have the router manual?
Did you change the default values?
Can you reach the router in another computer?
This should be the IP of the router… 
I can reach the internet through my desktop here which is on a cat5, not using wireless, but at the same time it’s running Norton and has never had the same issues. Both my laptops get the no/limited connectivity error. I know the Alienware is clean of any viruses/spyware, it’s only a few hours old. I pulled it out of the box, hit the WiFi button, and downloaded Avast as the first thing. I know the router (Linksys BEFW11S4) is working fine, as the other desktop on wireless connects, and is running avast fine (it did have a connection problem early on, but it went away by itself?).
I know it’s not Avast causing the problem, but I don’t know where else to turn. I tried 4 different antivirus programs now, and they all do the same thing. I tried searching the forums for someone that had any similar problems and all I could come up with is this: http://forum.avast.com/index.php?topic=20962.0
Is there any reason why the Default gateway isnt showing up? Is there anyway to manually input one or force it?
I just installed Avast for the 4th time now on the Alienware, and go figure, it works. ??? Blows my mind. As long as it stays this way Ill be thrilled. IMO Avast is the best freeware scanner out there, I’m glad its working now. Thanks for the help. 
Anyway, if you run the ‘repair’ of the network and you can’t succeed, please, post again and we’ll try to help you.
Glad you connect protected by avast 8)
even thought you are not experiencing the problem any longer I would like to add that the problem seems to be with your IP and not Avast, the IP you have is known for this kind of problem your IP should start with 192.168 and if you check your IP now that its working that what it is. So basicly you could have kept Avast and change your DHCP to a static IP and everything would work fine on both computers.
MounierNetwork
I have the same problem. After running the first DOS virus check the connection to the internet disappeared. The ipconfig showed no connection. Finally became so frustrated that I uninstalled avast and repaired the windows 2000 sp 3 installation using the original disk. Still no connection. Reinstalled the nic card driver. Still no connection. Tried the last known safe mode - nothing. Checked the event log and found the warning DHCP message “Unable to automatically configure the IP parameters … Procedure call table is invalid”. ERROR1006: “The volume for a file has been externally altered so that the opened file is no longer valid” Can’t afford to simply abandon this computer since too much work is stored there. There must be a way to resolve this problem. Help.
May I refer you to the post I just posted ???
MounierNetwork
Problem is not with the IP. The computer is connected to internet through a linksys router. Two other computers using this router connect to the internet properly. Problem is with what the avast program did to the networking files.
Why do you think that avast change any of your ‘networking files’?
Unless avast! identified some files as infected (which would clearly be reported) and you chose to delete them (or a similar action), avast! certainly didn’t do anything with the “networking files”.
But it did something to the file partition table. See the error message above. Hoping to hear about this from tech support. Apparently I’m not the only person who is having this problem. Problem is potentially very serious.
No, it didn’t, sorry.
First, avast! doesn’t perform any such low level operations, and second - the error message means something else than you think (the name of this error is ERROR_FILE_INVALID - it means something like that some file doesn’t contain what it is supposed to, or is completely empty, for example; the description, hardcoded to Windows, is rather confusing or even incorrect).
So what does the error message mean? How do I fix the problem? Still hoping to hear from some expects in tech support. Cause (avast virus removal) and effect (no connectivity - somehow volumes are changed in partition table) are clear in spite of what you say.
I’m afraid only the authors of the DHCP component know the real meaning of this message - but it certainly doesn’t have anything to do with volumes, or even partition table.
When you write “virus removal”, does it mean that a virus was detected during the scan and you told avast! to perform some action (such as to delete the infected file)? You didn’t mention it previously.
In Igor, you are talking to one of the avast programs developers, a member of the Alwil Team, so I think that would qualify as some expert in tech support ;D