Hello Empeg, the drivers available for your laptop are located at the following link.http://support.lenovo.com/vn/vi/products/laptops-and-netbooks/lenovo-g-series-laptops/lenovo-g550-notebook?c=1
It is important to know that there are no drivers for Windows 8 or 8.1 available, so it could be that your chipset does not support this Operating system. In order to get additional information it will be necessary to contact Lenovo.
The Intel Driver Update Utility you will be able to find it on this URL Intel® Download Center , however sometimes OEM systems do not allow the installation of them.
We recommend customers to use only the drivers provided by the system manufacture, in your case by Lenovo. The reason is because they make a lot of customizations to the drivers. Remember that our drivers are generic and the installation of them could overwrite those customizations.