Power but nothing else!!!

Any ideas please.
My 2000 td5 always started first turn. Never failed me in 5 years. However, twice now I've arrive at my destination, gone tod restart soon after and nothing!!
All lights on, fuel pump running, so power there, turn key.....nothing, no click, just nothing except the red engine light flashing . Give it 5 or 10 mins, turn key, starts first kick.
I've got my own thoughts on possible reason but prefer some expert insight.
Help please.
Thankies.

I am no td5 expert but my friend has one and last year had much the same problem. He did all the usual's like changing sensors, renewing injector harness, cleaning all connections but in the end it was an intermittent fault in the ECU.
So I would say have it checked out.

Thanks Bud. Was thinking along solenoid lines but worth a check first.