Host lost power, vm's reverted back to 3 month ago?

[devicemanager]

We have a SAN running esxi 5.5 with a few vm servers running on it and vcenter.  We accidentally had removed the power to the physical server.  When the physical server came back up none of the vms started automatically.  After further inspection a vm had an "!" mark, took a look at the summary tab and the server asked if it was copied or moved.  I selected copied and it started.  This then happened for each server in the list.  One server that I can tell has lost some data and reverted back a few months.  Can someone tell me what may have caused this?  Is there something I can check to make sure this doesn't happen again?

[GaneshNetworks]

Make sure the disk mode is not configured with "Nonpersistent".

[devicemanager]

No they are configured as Dependent.

[devicemanager]

Well after further review it appears that we may have a ghost.  Our developer is complaining that a couple directories are missing but some of the services are up and running that he developed.  Is there possibly a ghost of a snapshot?  All my servers that went down in the power loss experienced some peculiar issues but nothing this serious.  (maybe a firewall was turned on that I had turned off.  lost ip addresses etc.)  Any ideas?

[GaneshNetworks]

Analyze logs in VMs, which will help to direct you in a right direction. Because what happened to the servers were whole mess. Make sure that no one else logged in to the servers and made changes on them, just before the crash.