Dell Optiplex 390 (Intel i3-2120 Sandy Bridge) First time Hackintosher, can't get my installer flash drive to boot all the way up.

I've been trying to follow the Vanilla Guide to install High Sierra, but once it gets to this point, the system just reboots.

Specs:

• Intel Core i3-2120 3.3 GHz (Sandy Bridge)
• Intel H61 Express Chipset
• 4GB DDR3-1333MHz
• MSI GeForce GT 710
• SATA III PCIe 2.0 Controller Card (AHCI)
• 250GB Hard Drive

This computer's firmware is pretty braindead, and I can't seem to get anything to boot in UEFI mode. I'm using legacy boot, with an MBR formatted USB flash drive. Also, apparently the onboard SATA controller has no AHCI mode, so I've got a PCIE controller that does.

At this point I'm not even sure what parts of my setup I should be looking at; Clover install/config? kexts? config.plist?

Any help that might even give me an idea of what else I can try would be greatly appreciated.