The only thing that could be 'blocking' you in the way that you are mentioning is if you turned on Jumbo frames and your network/pc did not support it. That would explain it because you can send the standard 32byte frames for ping however when attempting to send the 3000,4000 etc bytes for jumbo the frames are being discarded due to size and non-compatibility.
Simple answer,
Use the pinhole reset on the back and hold in a paperclip for 10 seconds and start over.