Extruder won't heat up. Immediate failure.

[wstreet]

When I start up extruder I get the error below almost immediately. Nothing alarming happened on the last print other than it failed to heat properly and ended the print. Mind you I have never had a successful print on this machine yet so it seems that there is a setting that needs tweaking somewhere that I know nothing about. If anyone can provide some guidance that'd be great.

Error:Heating failed, system stopped! Heater_ID: 0
Error:Printer halted. kill() called!

This is a Prusa mk2 i3 build btw. I don't know much about all of this so if you need more info to help please let me know.

Thanks

[JohninLex]

Check your thermister on the hot end, and the connection to the board.