My internet connection suddenly stops working on hard reboot.

[raiserroofer]

Hi,

I'm using a desktop PC connected directly by ethernet to campus residential internet at my university (no router involved). I was in Steam starting up a game of Left 4 Dead 2 when -- before the game even boots -- my computer crashes to a black screen and a frozen loading cursor. I tried it all: Ctrl+Alt+Delete, etc., so I resort to the reset button. The computer boots back up as normal.

Once I'm in Windows (7), however, I realize that I am not getting any internet connection. I troubleshoot it, which tells me I'm getting DNS issues. So I figure it's not on my end, but just to be sure, I take the ethernet cable and try it on my netbook. It's working perfectly fine.

I uninstall my Realtek network driver: nothing. I checked that my IP/UDP is attained automatically, which it is, and I also did that cmd check to verify system files. So now, on my netbook, I just downloaded ClamWin virus checker and put it on a USBKey. It's currently scanning the desktop, but I'm not sure if it's going to find anything.

I have absolutely no idea what else to do. I know whatever caused this is on the software end of things, but I don't know what! Help!

 

[raiserroofer]

Program just found "Backdoor:Win32/Ursap!rts". Kind of bittersweet -- never thought I'd ever get a virus since I'm usually a pretty safe user...

 

[Saga Lout]

Program just found "Backdoor:Win32/Ursap!rts". Kind of bittersweet -- never thought I'd ever get a virus since I'm usually a pretty safe user...

More a Trojan than a virus, I think so something strong required. Try MalwareBytes from http://www.malwarebytes.org - recommended frequently on here and not just by me. After installing, updating and running both the Quick and Full scans with a restart in between, post back the logs if you have any doubts about what's left.

 

[Saga Lout]

Hi,

I'm using a desktop PC connected directly by ethernet to campus residential internet at my university (no router involved). I was in Steam starting up a game of Left 4 Dead 2 when -- before the game even boots -- my computer crashes to a black screen and a frozen loading cursor.

Is there any chance the Uni rules prevent use of that system for gaming or that particular game? It's a remarkable coincidence and may not be not related to the Trojan in your next post - they have nothing to gain and everything to lose by blocking your access to the Net.

 

[raiserroofer]

Alright thanks, I'll try MalwareBytes (free version is fine?) once this virus scan is finished.

I don't think this would be caused by the university. I've been playing games through this internet connection for years and it wouldn't just randomly bar me from using the internet on this one particular computer for playing a game at 1:00am. I can only conclude that this was caused by something I happened to have downloaded one way or another.

I really don't want to reinstall Windows...

 

[raiserroofer]

So MalwareBytes did not find anything, and even though I have one less trojan, the problem still remains. I tried renaming my Computer ID to see if the university gateway was cherry-picking me, but still nothing. (When I click on Full Network Map, I see me and two other computers with green lines towards "Switch", then a green line from "Switch" to "Gateway". Finally from "Gateway" is a grey line to "Internet", implying the problem lies in the Gateway. Not sure what that is. Hitting 192.168.0.1 does give me a D-Link login.)

The whole messed up thing about this is that I can connect to the Internet using the exact same port using the exact same cable just to my netbook. I just don't get what the issue is here.

:edit: I spoke too soon. I'm doing a full scan using MalwareBytes now, and it has found something. It will take awhile before it's finished but here's hoping.

 

[raiserroofer]

FIXED.

The problem: There was a DHCP conflict with the gateway. The gateway, whatever its hardware is, does not have conflict resolving turned on, so when I crashed, it thought I was still in session, and it wouldn't allow me connect with the same name and MAC address.

Solution: Change the MAC address AND computer name. I just put in some random numbers under the Device Manager --> Network Adapter --> Properties --> Advanced --> Network Location and BANG. Suddenly Internet.

 

[Saga Lout]

FIXED.

The problem: There was a DHCP conflict with the gateway. The gateway, whatever its hardware is, does not have conflict resolving turned on, so when I crashed, it thought I was still in session, and it wouldn't allow me connect with the same name and MAC address.

Solution: Change the MAC address AND computer name. I just put in some random numbers under the Device Manager --> Network Adapter --> Properties --> Advanced --> Network Location and BANG. Suddenly Internet.

There you go then - glad you got it sorted in the end.

 

[Ken1954]

I'm curious did this really fix the problem? I am having the same problem with my home network. I use STEAM in offline mode for Civilizaiton, and have isolated the identical problem to them. They actually prevent all computers on my home network from connecting to the internet while STEAM is active. It doesn't happen immediatly but over the course of a game or two without rebooting my computer the internet connection will be blocked. The network has worked for years without problems until the latest Civ game forced me to use STEAM. When I reboot my computer all other computers can then connect again.

Personally I would like to send Civ back the the manufacturers and let them know what crap they have unleashed. This is not a game that 'needs' the internet and doesn't need STEAM.

 

[Guest]

Best answer selected by fihart.