1994 Vauxhall Corsa Help! It won't start!

Engine Mechanical problem
1994 Vauxhall Corsa 4 cyl Front Wheel Drive Manual 90.543 miles

The other day, I started my 1.4 SRi, and there was a funny noise, like somthing was scraping against the timing covers, so I swithched the engine off and then attempted to start the engine again, but for some reason it would not start, it seemes as it's lost all compression, in all four cylinders, and after I asked my friend for a second opinion he tried a compression test and after taking the spark plugs out still no compression. Many have said that it might be my head, that his has warped, and after looking further into it it has had a new head gasket, because the cam pulleys were marked. It's unusually that it has just lost compression in all four cylinders. But a few times before this happend the car unusually started to smoke redicilously when the car was driving, I put this down to the EGR valve, after seeing a fault on a diagnostic computer, but the fault was cancled. Has anyone had the same problem? If so pleas can you tell me ehat it is! Thank You! Mathew Morris