These relate to different chipsets controlling different groups of SATA drives attached to that chipset's host controllers. This in not unusual on many boards. 1 through 4 are probably on another chipset that might support higher levels of RAID and are kept discrete from the one on 5/6 and the lone one on 7.Numbers 5 and 6 are ICH9R only and SATA 7 is controlled by Marvell 88SE 6117.
With just one hard drive in a system it should make no difference which port it is attached to as long as the BIOS sees it and it has the correct options configured.
That said, constant reboots are more commonly caused by such things as malware, bad memory, overheating and loose connections or an inadequate power supply. Blue screen stop errors can also be both hardware and software based so trying things in SafeMode is always worth a troubleshooting attempt.