computer won't boot after installation of DB9 adapter

I installed your driver for the DB9 serial adapter onto a new computer (Windows 7; EVGA x79 motherboard) and, upon restart, my 2 monitors are blank. I can’t even access the BIOS or start-up with the Windows installation disk.

The only thing I can figure out is that the DB9 serial adapter corrupted the BIOS. My question is, how do I fix it?

I unplugged the adapter and all other devices except for the monitors, and the computer still won’t boot.
The driver and device worked great on an older XP computer, so this was a little shocking.

I read this thread, but didn’t find a solution:…


Hi Gregory,

Thanks for contacting Plugable Support, we’ll be able to help. Sorry to hear about the shocking experience you are having with your machine refusing to boot! Because USB hardware and drivers are loaded after Windows, they don’t in any way interact with or effect the BIOS.

We’ll have to troubleshoot what’s keeping your system from booting, step by step.

First, connect just one monitor (to simplify your graphics system) to the on-board video port of your motherboard. Then connect just a keyboard, mouse and power.

What happens when you turn the system on? Is there any activity on the screen at all? You should see the BIOS message at the very least. If not you’ll want to test your monitor with another video source, and test the video output of the motherboard with another display if necessary.

If you’re not getting any output at all at this point, verify that there is power to the system. You should hear beeps from the motherboard when the system is starting,

Here’s a link to the EVGA X79 motherboard maunal which contains information on troubleshooting BIOS issues starting on page 25:…

And here’s a link to other EVGA manuals in case that’s not the correct X79.

Once you get the system to POST (power on self test), we’ll know more about what’s going on.

I hope this helps, let me know how it goes.
Thanks for your patience,

Plugable Technologies

Thanks for the response, Jerome.

It appears that the problem was a bad DIMM which decided to fail immediately after your driver was installed. Everything is back to normal, other than missing a DIMM.

… sorry to waste your time.

Hi Gregory,

Glad to hear that you’re up and running (though missing a DIMM). Let us know if there’s anything else we can do to help

Thanks for letting us know,