The network card in the Vostro 5480 computer is a Realtek PCIe network card. This card is popular and has been used in a number of other computers such as the Inspiron 3043. You can search for these on this website. You can download the drivers below which are Windows 10 driver both 32bit as well as 64bit which is for the network card in the Vostro 5480. The driver for the network card is easy to install and also reasonably small at about 27mb.
Vostro 5480 : Realtek PCIe GBE Network Driver
You can also find other drivers for the Vostro 5480 such as the card reader as well as the audio driver for the computer. You will need to download the driver below which is in a zip file. From there you will need to open the zip file and click on the file on the inside. This will install the driver or extract the driver to the main driver normally your C:\ drive. It creates a Dell directory and you will need to click on the directory and then click on the install file. This will take a few seconds to install the Realtek PCIe GBE network driver onto your Vostro 5480. Normally you will not need to reboot the computer. This driver was released in Oct 2015 and was the last driver released for this computer.