Mysql seems to be swithcing itself off?

[Dweezel]

Our server has developed another problem. Last night I had a message from someone using our website that instead of being able to see our product pages (mysql database generated pages using xcart software), the pages were just returning mysql connection errors. On confirming this I entered the sites cpanel and tried to access phpmyadmin which gave me the following error:

#2002 - The server is not responding (or the local MySQL server's socket is not correctly configured)

I checked 2 other sites that are hosted on this server and they were also giving mysql connection errors so I opened the WHM and restarted the mysql server. This only took about 20 seconds and solved all of these problems immediately.

About 3 hours later the problem was back however, and I had to restart mysql again. It was OK then for about another 10 hours but it's just shut down again. Mysql restarts are solving the problem temporarily but I need to find out what's causing this to happen.

Any ideas?

EDIT:
I've just been talking to our hosting provider and he said this would be due to a memory usage problem and that I should use an SSH client like Putty to try and find out what the problem is. I'm downloading it now but I've never used SSH before so any advice would be much appreciated.