I have an external serial modem that is run through a serial-to-USB
converter.
http://www.newegg.com/Product/Produc...82E16825134002
http://www.newegg.com/Product/Produc...82E16812107956
&Tpk=trendnet%2busb%2bserial

It will occationally hang, and the the only way to get back control of the
modem is to reboot the computer. When I query to modem from the control
panel, it says: "The port that the modem is using is currently open by
another application. Exit any application that may currently be using the
port."

I don't know what could be causing the problem. I have tried disabling all
other needless applications that run in the background, but that is still
no change.

Anybody got any ideas of other things that I can try?