Pull the emergency release and check the door to see if it binds up during up and down travel. Excessive resistance could overheat the motor and cause the garage door opener to stop.
You did not indicate the model number of your Craftsman garage door opener. Here is some information regarding the flashing LED light on a common Craftsman 1/2 HP model:
The light should normally be off unless you are in the process of programming. The flashing LED is an indicator that a fault was sensed by the control board. The number of flashes indicate certain potential problem areas as follows:
1 flash - a shorted or reversed safety sensor wire.
2 flashes - an open sensor wire or a misaligned sensor or a sensor obstructed for more than 8 seconds or mismatched sensor eyes.
3 flashes - a shorted wall control wire.
4 flashes - intermittent sensor signal (slightly misaligned)
5 flashes - RPM sensor issue or an overheated or failed motor
6 flashes - a failed logic board relay
These codes can be a useful diagnostic tool to point you in the right direction. For example, a difference between 1 or 2 or 4 flashes might quickly lead you to the cause of your safety sensor problem. But you do need to be careful since a power surge can sometimes accidentally trigger the system or cause an incorrect fault code so the codes should be used as indicators of a potential problem source and not an absolute confirmation. After all, I have seen 5 flashes on an fully operating opener, and a problem with either the RPM sensor or Motor should make it impossible for the door to close or open. I have also seen occasional flashes caused by interference from cell phones or other signals in an area.
If you are seeing fault codes that look wrong, or appeared for no apparent reason, you can reset the diagnostic memory by simply unplugging the opener itself for a couple of minutes.
If you need more help, resubmit your question with additional details.