Very happy with this cable which (after a bit of messing about) I now have working perfectly under Windows 7 64 bit.
Here's what worked for me.
1. I couldn't read the little driver CD on my computer so I just ignored it.
2. Pluged the cable in and let Windows try to find a driver from Windows Update. This failed, but then the Action Centre popped up and pointed me to a driver file on the Prolific website.
3. Downloaded "PL2303_Prolific_DriverInstaller_v1210.zip" as suggested by the Action centre. All installed OK, but on plugging the cable in I got a message "This device cannot start (code 10)".
4. Ran the install again, and chose the "remove" option.
5. Visited the Prolific website and downloaded "PL2303_Prolific_DriverInstaller_v130.zip" which is the latest version. Installing this version produced exactly the same error as V1210, so I removed it too.
6. Using Google I found this site: [...] which pointed me to [...]
7. With some trepidation I downloaded the file, virus checked it and ran the install. Install ran OK, so I plugged the cable in and it immediately started working perfectly !
Hopefully someone will find these instructions useful. The only reason I list the early steps is that they may work for you, and it's always nicer to use a driver from the manufacturer rather than a third party. BUT... the "cooldrives.com" file worked for me !
Please comment if you find this helpful...