Error while running Sony Vaio VGN-FW378J laptop having Windows Vista

Hi,
My laptop is a Sony Vaio VGN-FW378J that runs on Windows Vista Home Premium. It has WIDCOMM Bluetooth Software 6.2.0.5800 installed.
Whenever I turn my laptop on these 2 error messages pop-up.

btsendto_explorer.exe
Windows cannot find the target.
OK

BTTray
ERROR: Unable to start the Bluetooth stack service
OK
I Google them up and learned that it was a Bluetooth issue. So, I re-installed my Bluetooth software.
However, it didn’t solve my problem.
Please help me on this.
