If you do have another drive that can boot Windows 7, you can use the Disk Management tool to build a new system partition on your existing SATA drive. You have to shrink the existing partition, and create a new partition. Then you can copy the boot files to the new partition using bcdboot.
An APU is an auxiliary power unit. On-board APUs are small jet turboshaft engines that are started to provide electrical and hydraulic power to the aircraft when needed during periods when the engines aren't running. Some aircraft are designed...
APU is simply a term AMD came up with that refers to a CPU with an integrated graphics core. The AMD A series are APUs. It is a distinction that AMD wanted to make for their own processors. The FX (FX-8350) series are considered CPUs because they do not have an integrated graphics core.