Computer reboots when fax sent

Now when I sent a fax after the fax monitor says the 'call
is completed' the computer reboots. When this occurs the
fax service no longer works and is unavailable. I have to
uninstall and reinstall it to get it back. This event
started to occur after I install service pack 2, and
previously I sent faxes with out incidences. It does not
matter if firewall is on or off.

Any ideas what may be causing this and how to fix it.

Paul