If Nokia PC suite is available for your Nokia 6600 phone, go to the Nokia website and download the latest version of Nokia PC Suite, relevant to your phone.
Then - this is important - make sure that bluetooth on your laptop and phone is switched off (or if you are using a usb bluetooth device component on your laptop, unplug it) and then install the current Nokia PC Suite that you have just downloaded.
Once it is installed, plug in or activate your bluetooth device on your laptop and on your phone. If you had already paired the laptop and phone successfully, this pairing should remain and the laptop should find your phone automatically.
I had a similar problem, and the above solved it for me.
One final point though, Nokia advise that large files, such as music files, are better downloaded / uploaded to and from the phone using a USB cable rather than a bluetooth connection method - they obviously recognise that the phones have bluetooth limitations.
If its any help to you, the only way I have been successful using bluetooth connection between my Nokia 6230 and Vaio laptop is through the Nokia PC Suite interface. I know it's a different phone to yours, but I wouldn't be surprised if its the same for the Nokia 6600.
Hope this helps, good luck!
