I assume this robot has remained untouched from last season?
No cRIO image updates, etc.?
Do you remember the last time someone downloaded code to it at the end of the season, and was it run afterwards in competition?
Tethered directly, the DS-to-cRIO needs to use a crossover Ethernet cable, not a normal straight cable.
Are the DS Ethernet status lights coming on?
Did you try both ports with your laptop ping test?
Is your PC Ethernet port auto sensing?
I do have the DS firmware here