VM crashing intermittently

Hi,
So I just started this job and inherited this troublesome HP Proliant DL380e Gen 8 with VMware ESXi 5.1 server hosting two vms, Server1 and Server2.  Server1 is configured all jacked up with 4 500GB Sata JBODs on an embedded controller with NO RAID where 1 drive has the ESXi  and the other 3 are spanned into one drive to make a 1.5TB logical drive for datastore1(Server1).  This server randomly shuts off by itself and stalls at 95% as it powers off as well as when it powers back up.  Server 2 is on a separate controller in slot 2 that has 4 500GB Sata drives using RAID-5 to create another 1.5TB logical volume.  Once server 1 powers off, trying to control the ESXi host with Vsphere becomes completely unresponsive and after about an hour, Server2 powers off as well.  The box itself stays powered on but somebody has to go into the server room and do a hard shutdown and then turn it back on.  We can then power the vms back up with Vsphere, Server1 hanging out at 95% for several minutes until everything comes back up.  This happens once a day for the last 3 months.  I don't care for VMware so I'm no pro and am begging for help.  The C: drive has 44GB free and the data partition E: only has 12.9GB free.  They have the server set to manage the swap file automatically on C:.  Right now it's using about 1200MB for that.  Where can I look to figure out wtf is going on?  The other techs have even been on the phone with Vmware but those guys don't seem to be much help.  Any ideas?

Thank you!!