Correlation ID errors on certain ports on my SharePoint 2010 server

For the past 3 days, I have been receiving Correlation ID errors on certain ports on my SharePoint 2010 server.  It seems to be happening overnight.  For example, the site is fine at 10pm but at 6am the next morning, I receive the correlation id errors.  My Network Admin then restores the server from a "snap shot" taken the day before.

As far as I know and my Network Admin knows, there has not been a change to the server.  It has just developed on its own.  Any thoughts?

Snapshots are generally unsupported for SharePoint Servers. When you get one of these correlation ID errors, check the ULS logs at C:\Program Files\Common Files\Micorsoft Shared\web server extensions\14\LOGS. This will help you identify what the root cause is.