Engine won't start after two fuse changes and smoke...

Hi,

Last week I tried to turn my car on but the engine would not start. I changed the ECM fuse and it started up again. Yesterday, whilst coming to a stop (during driving) the car simply turned off and would not turn back on again. I saw the ECM fuse had burnt again, so I changed it again, however this time smoke began to come from the engine. So I turned the car off and disconnected the battery for safety.

Any ideas?

Thanks!