Why dell studio 1555 bluetooth not working after update?

This problem occurs due to unavailability of the Bluetooth driver software of unsupported driver software, as you said that you just update your laptop to the sp3 version and now your laptops Bluetooth is not working, so I suggest you to download the latest version of your Dell studio 1555 Bluetooth driver software from the dell official website. Open the dell website and then click on the download drivers and software option and then give the details of your Dell Studio laptop and then download the latest version of the driver software for your device then install it on your laptop and after installing, you need to restart your computer and then you will be able to use the Bluetooth on your Dell Studio 1555 laptop. Apart from this, may be this problem occurs due to Bluetooth hardware failure, so on hardware failure case, you need to contact to any nearest Dell service center, and they will assist you. I guess this information helps you.