I think that I have already installed all the drivers in my W520 but it still showing that some devices are not installed -
In "Other devices" I have the folowing four entries:
- Base system device
- Biometric Coprocessor
- PCI Serial Port
What other drivers are needed still?
Download the "System Update" application from this link, install it, and run it.
This Lenovo application will then fetch the four missing items you list and install them automatically. It will also check to make sure all the other drivers are up to date.
If you need a list of all the drivers available for your machine, you can get it (and the drivers themselves) from this link which is the Device Driver File Matrix (DDFM) for the W520.
Else, just download "System Update" and let it do all the work for you. In fact, you might even have that application on your computer already - just click on the Windows 7 orb (the coloured ball with the flag on it) and type "System Update" into the search box, if it is installed, you will see it appear in the results list. If it appears, click on it and run it.