This sounds like a classic case of overheating. Before doing anything else, open it up and clean the fan. If your problem persists, change the thermal paste between the heat sink and the CPU.

The computer shutting down after the fans have been spinning very fast for a while is a clear indication of cooling problems. As is the fact that the machine will not turn on again immediately —it needs to cool down first.

I know you have a cooling pad but it might not be enough if the fans are clogged up or if, more likely really, the heat paste is old and dry.

Update:

Having seen the image you just posted, it is definitely a cooling problem. You should never be seeing temperatures around 80C and in your case, 81 degrees is only 2 degrees below critical temperature (181F ~ 83C).

This sounds like a classic case of overheating. Before doing anything else, open it up and clean the fan. If your problem persists, change the thermal paste between the heat sink and the CPU.

The computer shutting down after the fans have been spinning very fast for a while is a clear indication of cooling problems. As is the fact that the machine will not turn on again immediately —it needs to cool down first.

I know you have a cooling pad but it might not be enough if the fans are clogged up or if, more likely really, the heat paste is old and dry.

Update:

Having seen the image you just posted, it is definitely a cooling problem. You should never be seeing temperatures around 80C.

This sounds like a classic case of overheating. Before doing anything else, open it up and clean the fan. If your problem persists, change the thermal paste between the heat sink and the CPU.

The computer shutting down after the fans have been spinning very fast for a while is a clear indication of cooling problems. As is the fact that the machine will not turn on again immediately —it needs to cool down first.

I know you have a cooling pad but it might not be enough if the fans are clogged up or if, more likely really, the heat paste is old and dry.

This sounds like a classic case of overheating. Before doing anything else, open it up and clean the fan. If your problem persists, change the thermal paste between the heat sink and the CPU.

The computer shutting down after the fans have been spinning very fast for a while is a clear indication of cooling problems. As is the fact that the machine will not turn on again immediately —it needs to cool down first.

I know you have a cooling pad but it might not be enough if the fans are clogged up or if, more likely really, the heat paste is old and dry.

Update:

Having seen the image you just posted, it is definitely a cooling problem. You should never be seeing temperatures around 80C and in your case, 81 degrees is only 2 degrees below critical temperature (181F ~ 83C).