Not only the Prolific might not work - it PROBABLY will not work! So many counterfeit chips out there and the Windows drivers really do care.?
Get a known FTDI (?) cable. I can't tell you how many people have wasted days, weeks and months with bad cables and RS-323 cables.?
As an aside I have used a Befoeng programming cable with the connectors cut off and RX and TX to the tip of the 3.5 mm plug and it worked just fine with my IC-7000.?