A 4000 should have web interface with no drives, but NO link.
Does the disk led blinks normal like disk activity during startup?
Does the Sys led blink every ~2 sec?
The only think I can think of is: No SYS or Disk LED actifity = failed System Board
If all execpt LINK, may try replacing the lan controller chip. But that's not a given. It would be cheaper to buy a used unit from ebay for parts.