1 Two beeps is normal on the 4th Series.
2 What BIOS version do you have?
3 What LAN drivers do you have? Did you install the ones from the CD or from Intel Web site?
Is probably best if you install the latest drivers from the Intel Web site.
4 What operating system do you have? And service pack?
I had the same problem before. It can be quickly fixed by updating your LAN driver.
Go to system properties>>Hardware>> device manager>> Click netwowk adapters>> go to "Realtek PCIe GBE family controller" properties>> click "driver" tab>> then update driver. This would take a minute or two and then everything will be good.
And the two beeping sounds at boot up is normal for this model.