VB6 Comport problem using Windows 7

I have a VB6 application running on XP that uses the comports. I have installed VB6 on a Windows 7 machine, and cannot get VB6 to recognize the comports. I am using USB to Serial adapters, and they are recognized, and work with others Windows 7 applications. I am running VB6 in the XP compatibility mode, and have tried running it in XP virtual machine but neither works. Any ideas?

Thanks in advance,

Gary