http://support.lenovo.com/sg/en/products/desktops-and-all-in-ones/3000-j-series-desktops/3000-j200-desktop?c=1
Select Component: Networking
As you can see there are 3 drivers, for different LAN controllers. You will have to find out which brand of controller your board uses (by looking at the board or in the manual)
If you can't tell what it is then install all 3 and then uninstalling the two which are not the listed network device in device manager.