When you experience this problem, you have to restart Windows XP to get infrared communications working.

This behavior can occur if Serial.sys restores your infrared settings, but they are reset when the NDIS driver tries to restore your settings.

To resolve this problem:

1. Use Regedit.exe to navigate to
 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ACPI\PNPxxxx\yyyyyyyyyy\DeviceParameters,

 where PNPxxxx and yyyyyyyyyy are specific to your infrared device.

2. On the Edit menu, press New and DWORD.

3. Set the Value Name to SerialRelinquishPowerPolicy.

4. On the Edit menu, press Modify, and set the data value to 1.

5. Press OK.

6. Exit the Registry Editor.

7. Shutdown and restart Windows XP.