Hi LOOK281,
Welcome to Microsoft answers.
• Who is the manufacturer of the USB to serial adapter?
The drivers individually depend on the device manufacturer.
I would suggest that you check if the device is compatible with Windows 7 or not, you may refer the link below:
**http://www.microsoft.com/windows/compatibility/windows-7/en-us/default.aspx**
If the device is compatible with Windows 7, you may try connecting the device to the USB port and try updating the drivers and check.
Refer the link to update the drivers: Update a driver for hardware that isn't working properly:**http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly**
If the issue still persists, then I would recommend that you contact the device manufacturer to check if there are any new updates or patches available that would support Windows7.
Swathi B - Microsoft Support.
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