100% Tested Solution... I have tested it under Microscope!
- Do a full Windows Update. One
Unknown Device
entry from Device Manager would vanish. - Install Free Fall Sensor driver to remove another
Unknown Device
entry.
Note: The website hasn't listed Dell Studio 1558 as Compatible System, but the sensor model is exactly same. - Install Ricoh Card Reader driver pack 2.15.17.02 (have 3 drivers) to remove other two
Unknown Device
entries. After system restart, you can test card reader by yourself. It'll work.
Note: Pay attention to the version number and install only this version despite the fact that its not listed under Windows 8. - As of now, your device manager will not show any
Unknown Device
, but you know you are unable to use Bluetooth. For that, install Bluetooth Driver V12.0.0.1600 (again pay attention to version number despite its old) and update it immediately using Windows Update (Windows Update part is important). After restart, you'll be able to use all features of bluetooth.
Note: I am aware that I have given link to Asus's website. Actually, both companies don't manufacture Bluetooth modules by themselves.
Done!