This is not a Microsoft binary. You'll have to contact the serial-usb adapter vendor for their latest drivers. Prolific is not making a Vista compatible version.
John E [MSFT]
- Proposed as answer by Drew Coppock Thursday, May 14, 2015 2:52 PM
I have a prolific ser2pl adapter that I plugged in to a usb port on my inspiron 1525 running vista - the long and the short of it is this: Windows found a suitable driver when I clicked the option to let it search online. I had my driver for ser2pl.sys ready to go from my XP system, but could never get vista to use it... all's well that works well, I say.