Thanks guys for your replies. I checked everything I could think of down to the port settings, IRQ's, baud rate settings, admin rights, etc(no conflicts). I dumped any PDA, Cell phone, FAX or other programs that I thought might hold the COM ports open but still nothing. I even bought a serial to USB cable and created other COM ports....access still denied...Tried connecting up with security software turned off and uninstalled - still no go. Finally I tried hooking up the Icom interface to an old laptop I had running the same XP OS....worked on the first try. Looks like I'm going to just re-format the HD on the desk top, re-install XP and start from scratch. Thank you all again for your time!