All my websites are down. They are all showing 504 gateway timeout errors. When I stop nginx for a while then restart it - I get to view a few pages on some sites then they all go down again.

I'm running Plesk 12.0.18 - the server has been running for a year without any problems. This just suddenly started today. The only work I did yesterday was on some PHP code in one file. I've deleted that file today just in case, but it's made no difference.

Last week, there were some weird numbers coming out of the server such as 1209849380% CPU usage and 479% Apache usage. They stopped after a few hours though.

What can I do? My hosting company will do nothing. They've referred me to Odin but have said I may not even get a response!