In some instances the malware will change the settings to use a proxy server. To see if this is the case:
Open Internet Explorer. Go to Tools>Internet Options>Connections Tab. Click on the "LAN Settings" button. IF there is a check in the box next to "Use a proxy server for your LAN", uncheck it. Click "OK". Then "OK", again.
Open Firefox. Go to Tools>Options>Advanced. Click on the "Network" tab. To the right of where you see "Configure how Firefox connects to the Internet", click on the "Settings" button. Put a tick mark next to "No proxy". Click "OK". Then "OK", again.
If the settings hadn't been changed, try the following tools, in case malware is still posing a problem.
Download the below and save them to his laptop. If you're unable to do so, you're going to have to use another computer and transfer the tools to his. (Using a CD/DVD or Flash Drive)
Download and run the "Rkill" tool. You only need to launch one file, in order for it work. If you have no success running rkill.exe, try the next. When Rkill runs you will see a command prompt window similar to this. IF one DOES work for you (immediately) run a Scan with Malwarebytes' Anti-Malware. (See below) Do NOT reboot after running Rkill.
Rkill's purpose is to terminate offending/malicious processes. A more detailed explanation of what Rkill "does and doesn't do", can be found at the bottom of the Rkill download page.
You're also going to scan with Malwarebytes' Anti-Malware (free). The direct links for the installer and manual updater are listed below. To avoid any problems, rename the installer, prior to transferring it to his laptop. Rename the mbam-setup.exe to something such as toms.exe, if you wish. Don't forget to update, after the transfer.
Manual Update link
I would also suggest scanning with SUPERAntiSpyware. SUPERAntiSpyware FREE Edition can be downloaded from here.
If you run into any problems, please post back and let us know..
I am setting up a salesman's laptop to use our company VPN.
Compaq Presario (don't have the model number at hand right now)
Win XP home sp3
No obvious anti-virus software installed
His default browser is Firefox ( version 3.6.17), and, while he can connect to the VPN, the app he needs to run will not work as it should. I tried using Internet Explorer, but that won't even run (loads, then just terminates).