If your PC is running Windows 2000 or XP and you get a message asking whether you have administrator level authorization, please check if you have logged into the OS as an administrator. There may be cases when overwriting registry data is not allowed even if your account belongs to the administrator group. If that is the case, you have to edit your registry. To edit your registry, please take the following steps.

For Windows XP:
- Log into the OS with the current account and select "Run with the specified file" from the Start menu
- Type "regedit" and select "OK"
- A window called "Registry editor" opens. Activate "HKEY_LOCAL_MACHINE" by clicking on [+]
- Click on the [+] located at left of "SOFTWARE"
- Select "PlayOnline" and choose "Access Authorization" from the Edit menu
- A Window called "Access Authorization to PlayOnline" opens. Select your account in "Group name or User name" and check "Authorize" for full control and then select "OK"
- Restart your PC and try to run PlayOnline

For Windows 2000:
- Log into the OS with the current account and select "Run with the specified file" from Start menu
- Type "regedt32" and select "OK"
- A window called "Registry editor" opens. Activate "HKEY_LOCAL_MACHINE" by double-clicking it
- Double-click the "SOFTWARE" folder and select "PlayOnline"
- From the security menu, select "Access Authorization"
- A Window called "Access Authorization to PlayOnline" opens. Select your account in "Group name or User name" and check "Authorize" for full control and then select "OK"
- Restart your PC and try to run PlayOnline