Problem sending a fax

After years of sending/receing faxes, today I tried to send a fax, and
nothing happened. I have a Dell Dimension 8400 with a Conexant D850 56K v.9x
DFVc modem.

When going into device manager, everything seems fine-- no obvious
conflicts. When I tried diagnostics for my modem, the message I received was:

"The port that the modem is attached could not be opened. This may be the
result of a hardware conflict."

Another error message:

"Opening the modem device failed with error 000005aa"

I uninstalled the driver, any reference to the modem in device manager, and
rebooted. The PC found my 'new' hardware, and reinstalled the driver, but
with the same results.

No new hardware. Recently installed TurboTax for tax year 2008, but can't
see how that would be a problem. Dell's Modem Helpware also tells me that a
software application may be using the modem or that there may be a hardware
conflict??

No spyware using Webroot Spysweeper. No virus using McAfee.

Thanks for your help.

Thoughts?

Thanks!

Howard