Keeps on rebooting after Apple logo?

My iPhone 4s keeps on rebooting after the Apple logo, I plugged it into my iMac and PC, for iMac it comes up with Error code 2001, for PC it comes up with Error code 21.

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0