@azureeyedtech Ok, let’s take this one step at a time.

First off: If you’ve used the image type “Multiple Partition Image - Single Disk” only (are you sure about this ???) then it’s near to impossible that FOG has done anything harmful to your source disk! But if you’ve switched over to “Single Disk - Resizable” somewhere along the way then might have changed anything on disk, although we haven’t seen it do anything harmful on upload in a long time. So please tell us, have you ever run an upload task on this machine when image type was “Single Disk - Resizable”? We need to know.
Keep in mind that you cannot switch image type between uploading and downloading the image. If you change the type you need to re-upload the image again!

The PC had secure boot disabled, UEFI disabled Legacy Boot enabled […] I switched the PC host back to UEFI and secure boot and it failed to load Windows

You cannot just switch from UEFI to legacy BIOS and back as you like. These setting needs to be set prior to installing an OS on disk hand have to be left alone after that. UEFI is looking for a FAT32 formated partition to find the boot loader file(s), while legacy BIOS on the other hand tries to find the boot loader code in the MBR. So again, you need to decide which way you wanna go UEFI or legacy BIOS and then leave things as is. In your case it sounds as if the OS was (pre-)installed in UEFI mode. Then you need to run FOG in UEFI mode for this client as well!! FOG can do this. On PXE boot the FOG DHCP server is handing out the correct boot binary to the client depending on it being set to UEFI or legacy BIOS. But if you use a different DHCP server then you need to set this up yourself: Instructions see here…
Secure boot setting is different. You actually need to and should be able to disable secure boot as FOG is not able to handle this. Most people just leave it disabled but AFAIK you may enable it after having uploaded/downloaded an image from/to a client.

So what to do now?

First and foremost find the image on your FOG server (hope you have not overwritten it by several uploads) and make a backup copy of the whole directory. Should find it in /images/<IMAGENAME>. Hope we never need it but you never know. Might be the last copy of your original partition layout we have. While you are there, post the contents of the text file d1.partitions that you find in the image directory. Plus run ls -al /images/<IMAGENAME> and post listing here. Change image type to “Multiple Partition Image - Single Disk” and leave it like that for now! Set UEFI/legacy BIOS on your initial source machine to whatever it was before you played with it (I suspect UEFI) and see if it boots up Windows properly again. Setup your DHCP server to serve both UEFI and legacy BIOS machines with different boot binaries (see the wiki article above). To see if the UEFI boot partition is still there boot the machine up using a Linux live CD/DVD open a terminal window, become root/sudo and run the following commands: mkdir -p /mnt/boot mount -t ntfs -o ro /dev/sda1 /mnt/boot find /mnt/boot umount /mnt/boot gdisk -l /dev/sda

Take a picture of the output on screen and post here.

By the way, are you sure you can actually do what you are trying here? Cloning one image to several Alienware machines with a pre-installed OS that cannot be activated through normal windows keys. Maybe I get you wrong here but this sounds as if it is going to cause much trouble anyway.