PC Gets Restart when any characters are sent to Bluesmirf

I am using Windows Xp and i have a Bluetooth dongle. I have installed it correctly.

i can connect the Bluesmirf with Hyperterminal and the Green LED starts glowing while the Red LEd goes OFF.

If i try to sent any characters to Bluesmirf then the PC gets automatically restarted. Is there any problem in Bluesmirf or in my Bluetooth dongle.