WiFi shield not present

Hi

I have a problem with my Arduino WiFi shield after I upgraded the firmware
When I put an LED on pin 13 it shows that the WiFi shield not present, and when I remove the LED it works just fine.

can you please help me

One LED should not affect the overall current draw much, but perhaps you're powering the whole circuit with a power supply not up to the task. It's my only guess with no other information.