I bought this adapter you have, but it does not work under Windows7.
I download latest driver from profilic syte:
Run, setup, but in Device manager this converter have yellow mark and status "Error Code 10".
In drivers manual file PL2303_DriverInstallerv1.5.0_ReleaseNote.txt
If you are encountering yellow mark (Error Code 10) for device in Device Manager, you need to contact the cable vendor or manufacturer for Prolific genuine chip validity. Prolific does not manufacture any end-user cable products and will not provide direct support to end-users.
Prolific highly suggest end-users to contact the user product manufacturer for service and support.
Prolific Technology Inc.