Vista refuses all my internet connections

Hello everybody,

I've got this problem for at least a month now and I haven't found a
solution yet. I can't remember the exact date or what I had changed on my
system. I always used to connect to the internet by my mobile phone using the
USB-data-cable and the mobile phone's modem-drivers. My personal firewall (in
this case Kaspersky Internet Security 7.0) was always activated, Windows
Firewall deactivated. But from one day to the other Vista refused it with the
following error in the "Application" log (Computer Management\System
Tools\Event Viewer\Windows Logs):

Source: RasClient
Event ID: 20227
Message: The user JANUS\Sebastian dailed a connection named VMCLite which
has failed. The error code returned on failure is 31

Precedent to this message there are always 4 entries of type Information
from the RasClient saying that I try to establish a connection and a link to
a Remote Access Server and that I have successfully established a link to a
RAS. These messages have the Event ID's 20221 to 20224.

I have already deactivated my firewall, in fact I even have terminated the
process. I also made sure that the Windows Firewall is deactivated. This
steps unfortunately didn't solve the problem.

Then I have reinstalled the modem-drivers - no difference.
I have tried a complete new hardware, a mobile broadband USB modem (in this
case the Novatel Ovation MC950D) using a different network - same result,
same error.
The hardware itself is functioning, both the devices are working fine with
another, a Windows XP system.

Firstly, I have googled for my problem and I have found only 1 good
discussion that came to a conclusion: reinstall the operating system. This is
in no way an option for me. What assures me, that the problem won't appear
again? I am no friend of a complete operating system reinstall - I keep my
system highly clean, organized and customized.

I am running Windows Vista Ultimate (x64; english). I don't think that my
hardware would be relevant to this problem, but if you think it is feel free
to ask for whatever information you need to know.

Oh and by the way, sharing the internet connection is no option for me, too.

Thank you very much in advance!

Best regards
Sebastian