Adapter stopped working for unknown reason

I have a Lenovo Windows 7 PC, ATI Radeon HD 4250 display adapter and 2 identical viewsonic VX2370 monitors.

I have been using a Plugable 2.0 Display adapter to connect a second monitor while the first monitor was a standard VGA connection to the internal VGA. It stopped working. The green light was not lit. I tried other USB ports. Restarted and no joy. I took the USB adapter to another PC and it works, green light and all. Took it back to the original PC and still no go.

So I bought a new Plugable displaylink dual head USB 3.0 adapter. The green light comes on and I hear the USB tones for a device connected. I see the installer running. I decide not to wait for Windows update I run the driver on the CD. Nothing.
I have plugged in to the VGA port via the adapter and I have used an HDMI cable both in combination and individually. Nothing works at all.

What can I do? I am a big fan of your products I have them installed at many of my client installations. I hate to give up.

Thanks in advance for any help.

Bob

Hello Bob - I am about to follow up with a direct message asking for logs. Please stand by.