I had the same problem with an adapter (Sabre) that I bought from Tiger Direct for $14. But then when onto the manufactures website for an updated driver and know it works fine, heres the driver download, unfortunately I can't remember the model number of the driver.
PL-2303 Driver Setup Installer, Prolific Edition
Setup Installer Revision Note History
. Supports the following Windows OSes:
- Windows 98SE
- Windows ME
- Windows 2000 SP4
- Windows XP SP2 and above (32 & 64 bit)
- Windows Server 2003 (32 & 64 bit)
- Windows Server 2008 (32 & 64 bit)
- Windows Vista (32 & 64 bit)
- Windows 7 (32 & 64 bit)
NOTE: For Windows 7, please use RC build 7100 or above.
. USB host controller
. Device using PL-2303H/HX/X version chip
Supported device ID and product strings:
. VID_067B&PID_2303 for "Prolific USB-to-Serial Comm Port"
PL2303 Driver Installer v18.104.22.168
Changes from Installer v22.214.171.124:
. XP/2K/2003 (WDM Driver) v126.96.36.199:
- supports both 32 and 64 bit OS
- pass Microsoft XP Windows Logo Test (WLK 1.4)
. Vista/7/2008 (WDF Driver) v188.8.131.52:
- pass Microsoft Vista/Win7 Logo Test (WLK 1.4)
Installer & Build date: 184.108.40.206_20090723
- Chinese (Traditional)
- Chinese (Simplified)
Prolific Technology Inc.