You might have to go into the device manager on the laptop and adjust the port settings for the usb to serial port adapter.
what USB adapter did you get might be able to help you out...
Also you can look to see if there is a docking station/Port Replicator avalible for the laptop with a serial port on it.
or even this
http://accessories.us.dell.com/sna/p...=baynoteSearch
Dan