PC Set to Boot at Specific Time *Sometimes* Gets Stuck in BIOS

We have a computer lab with 6 PCs and 1 PC acting as a Print Release Station (PRS).  The PRS is imaged via ZenWorks.  The image uses Deep Freeze to prevent changes and is set to shut down the PRS at 4am.  BIOS is set to boot it at 6am so it will be ready for students to use.  The problem is sometimes it does not finish that boot at 6am.  It stops in the Dell BIOS screen about 3/4 the way through. 

This happened about three or four times over the course of several months.  Maybe once every three weeks.  My boss told me to swap it so I did.  I installed the PRS image on another machine and swapped it. 

About three weeks later it happened again.  The same problem with a different machine.

Both systems are O745s.  Both have the same image. Both are connected to power and the network in the same way.  The difference is the hardware, but they have the same specs.

It seems very unlikely that two PCs would have the same problem.  Which makes me think there is something wrong with the image, but the image shouldn't be part of the equation while the system is in the BIOS stage of booting.

I set the new PRS to boot at 5am so it will boot before the other PCs in the lab, in case it is a power issue. I checked the logs and the only thing that seemed odd was the WSTime reported that it couldn't sync.  But that should affect WHEN it would boot, not how far into the boot it would go.

Is there anything from the BIOS or hardware side you guys can think of that I should check before I tell the Image Team their image is breaking the PRS?

Thanks!